playing an openinng from both sides

I see a lot of GMs saying that they had played this opening many times from both sides.I wanted to know if doing this would improve my chess?I tried it  as

I  play french defense against 1e4 and like advanced and rubenstein variation for black and I also play c3 sicilian (so I played french defense advanced variation a couple of times as white [1e4 c5 2c3 e6 3e5 d5 4d4]) and I was not at all comfortablewith my opening.How should I improve this?

No matter what your repertoire is, there will always be a minimum of one opening variation that you must be able to play from both sides.  It might be something as unorthodox as the Grob, but there will always be a minimum of 1.

Here's the proof:

What do you play as White on move 1?  (Let's say the player answers 1.e4)

Ok, as Black, what do you play on move 1 against 1.e4?  (Let's say he says 1...c5)

Ok, as White, if you play 1.e4, what do you play on move 2 against 1...c5?  (Let's say he says 2.Nf3)

Ok, as Black, what do you play on move 1 after 1.e4 c5 2.Nf3?

Etc.  Just continously ask that same question from each side.

For me, I overlap in 3 spots.  Najdorf, Taimanov, and King's Indian Attack vs Sicilian.

I have an overlap in the Qc2 Delayed Meran. So I play that opening from both sides and need to know it decently because it comes up frequently.

I kinda dont have my own openings. I play random moves.