Stuck around 600 rating

Chess is not about intelligence. It's about skills.
You need to know popular openings, standard constructions in the opening stage and endgame.
Of course, someone should have some brains to play this game, but it doesn't mean that chess ratings can tell us about IQ or something like that.
I don't want to stop you from learning chess, but I'd like to warn you, that this stake may be too big.

I didn't really analyze your game, because it would take too long and I am not the most qualified person to help. But just that particular situation caught my attention because not only you missed mate (it happens), but because of how fast you moved every move and especially that one in a critical position with so much time on the clock. There were other missed opportunities for both sides and you both had way too much time on the clock to be on move 40 making that many mistakes (again, it's fine to make mistakes, that's how you learn, but at least make a well-thought mistake lol)

As far as opening goes... you can study a little bit, it's part of the game, it might help you get an advantage in the middle game but if you don't know how to convert that advantage into a win it's not much use. As I said you can spend some time looking at openings, but don't memorize it, try to understand what the specific opening is trying to accomplish. Much more important than knowing specific opening lines is knowing and understanding Opening Principles. That way you can be ready for pretty much 99% of the openings your opponent plays against you. Maybe you'll fall for a trap or trick here or there every once in a blue moon, but then you learn from it and don't fall for it again.

Since there are many many many different moves that can be played, it's not possible to memorize all of them. Take the spanish Ruy Lopes opening, for example. You have the Morphy's defense variation, the Berlin defense variation, the exchange variation, among others. And that's just one opening. Then the italian has a bunch of variations that have sub variations, which in turn branch to other lines, etc etc... Same goes for Sicilian, french, scandinavian, caro-kann, english, queens gambit, list goes on

That's why it's important to learn the opening principles: control the center, develop quickly, get your king to safety, etc... because all good openings are based on these principles. Sure you can go in depth for a specific opening you like. If you're constantly playing the same opening and analyzing your games you'll get more knowledge on that specific opening and that's fine. But if you want to get better at chess your time is better spent on those other things I told you to focus on. With time and experience you'll develop a couple of pet openings that you'll play more often and know to punish your opponents quickly and get a deciding advantage straight out of the opening. But then again, if you can't convert that advantage by know everything else I wrote here, all that time spent focusing on openings was all for nothing

When people say "don't study openings," they're saying don't invest a ton of time into detailed memorization of multiple variations, and don't bother going extremely deeply into the opening's main line.

Learning the first several moves of an opening's main line, along with understanding how it's intended to set you up for next steps, are things you should feel comfortable doing right now if you have the interest.  It doesn't hurt to know a few main-line moves of one good opening for white and a couple for black (since you'll have to be able to respond to d4 and e4.)

But, and this is essential, whether you do this or not, you MUST start with basic opening principles, because no matter how much of an opening you learn, you'll have to be able to do something sensible where your knowledge runs out, or when your opponent does something you do not expect.

If you're open to a book recommendation, I'm a huge fan of John Emms' Discovering Chess Openings: Building opening skills from basic principles.  This book REALLY starts from the beginning (looking at every possible first move and analyzing why it's good or bad) and adds basic principles until it works up to a discussion of a sampling of popular openings to see why they work well.

Beware of people spending like 20 min to think on 30 min, after the game block them

Never resign until checkmate is inevitable. I blunder, but I usually don't just resign. I play on

Recognizing your blunders is very important! Think about the moves carefully before you make them.

Kapivarovskic I saw this move right away. Your explains help. Im stuck too. Mine is mire then frame of mind Im in. Thank you

Kapivarovskic Here is the file i forgot to add Well, I cant attach it. But it was 42) Qg8 mate a cpl moves earlier maybe

It sounds like a joke, but in chess, every time we make our move, our opponent gets to make one too. I have only been playing for 4 months, and I almost quit because of discouragement not unlike you have described. I would see so much content about all of these different openings and controlling the center, studying tactics, etc. I was becoming increasingly frustrated, because I felt like I was constantly engaging in chess study, but I still lacked any fundamental understanding of what I was actually doing when I would play. I would also experience the fear of "odd" moves and how I could easily lose all confidence in myself during games. To revert to my initial statement, I noticed my games became much more "playable" when I really tried to stop having those "oh no, I didn't see that move coming" every game and multiple times per game. I realized that I was rarely (sometimes almost not at all) really considering my opponents plan or why they wanted pieces on certain squares. I always make sure the first thing I do before every move I make is try to see what my opponents best move is or what strong moves might be waiting behind the position. It makes all the difference when you really say "ok, I see that are trying to target this square because they want to accomplish this or that", whatever the case may be. Doing this is fundamental because you can actively focus on weakening the opponents plans in while asking yourself how you can achieve that while creating positions that help your plans thrive. As far as openings go, you should first look at games you've played and assess how you like to play. Do you do well with strong defensive positions or do you like to create games that allow for more tactical ideas? For instance, I decided to stick with the Queens Gambit opening for white because it often gave me strong center control while creating the very opened positions that I wanted. I noticed that sticking to one opening I liked and seeing why I was able to often control the game quickly allowed me to start seeing the common moves that arise after the initial pawn moves. It makes the game a lot easier to play when you practice one or two openings you like for black or white because you see how you begin games with confidence and you aren't feeling so lost anymore. I'm going to conclude this by including a link to an article that helped me understand why I wasn't "getting it." Hope this helped in some way! https://chessfox.com/14-habits-of-strong-chess-players/