They are both hard ngl
blitz seems way harder than rapid
Not really. 3 min blitz is as easy as 10 min rapid pending: you warm up a bit with a no rating game, DON'T play when you are tired or have had bad emotions or problems. Most players blunder games due to not following these simple rules. I don't as well as I use chess to relax after a hard day. If I am energetic my winning streak can be 5-6 games in a row before I lose interest or lose a game.

Blits it definitely the hardest. People like to say " ur just not good under quick time". But bullet is what I'm best at. I have a much better chance beating a 1000 in a 10 minute game than I am to beat a 900 in a 5 min with 5 sec add ons each turn. This is because in rapid more people cheat. Really good players don't usually play rapid because of this. People play better moves in 3 minute games than 10 at the same rating. Everyone should get an extra 200 points in blits.

Not really. 3 min blitz is as easy as 10 min rapid pending: you warm up a bit with a no rating game, DON'T play when you are tired or have had bad emotions or problems. Most players blunder games due to not following these simple rules. I don't as well as I use chess to relax after a hard day. If I am energetic my winning streak can be 5-6 games in a row before I lose interest or lose a game."
Says the guy that's barely an 800 in blits and almost 1200 in rapid

Consider learning some blitz-specific openings that are designed to be aggressive and put pressure on your opponent early in the game. These openings can be effective in blitz games where there's less time for deep strategic planning.

Two reasons I can think of. 1. People's blitz ratings are always turned into their rapid ratings and since blitz is more difficult and different to rapid people's ratings generally shifted down regardless of their rapid skill 2. More players in blitz because it takes less time, larger player pool with different rating standard for same skill

15+10 is much harder than blitz , if you can play 15+10 very well,then you really have some level in chess
I use blitz as my "drunk" mode. I'll play at midnight 6 beers deep so there is that. Plus I learned chess as a kid and teen without ever playing time controls. I'm 600 something blitz but 1300 something in rapid. However Rapid is my "serious" rating.
If you want to be decent at blitz (3-5 min) you have to play bullet unfortunately. Not a lot and not necessarily rated but when it goes to the wire and in the last few seconds of the game intuition plays a big part in blitz. Time and time again I have been in a situation where my opponents were able to churn out 10 moves in 3 seconds and that would happen to be the best moves while I am sitting there cluelessly trying to figure out what just happened. I was often wondering if I am playing against humans or am I playing against aliens. Bullet seemed to have helped overcome this problem.

The blitz pool is very smart when it comes to finding tactics and punishing mistakes. Getting better at blitz also helped me improve my rapid rating from 1500 to 1850, while in blitz my rating is 1500

https://www.chess.com/forum/view/for-beginners/blitz-seems-way-harder-than-rapid#comment-51850752
When My rapid rating was just below 900 at around 880, my blitz rating was 297 and let's not get started on how playing bullet felt like I was below 100 elo and forgeting the rules of chess.
500 rated blitz player be better than 1000 rated rapid players from my experience. its not even close.
Not exactly, I am 600 blitz, only 700 rapid XD, blitz and rapid rating is pretty much the same at the lower levels...