@1
"I was wondering what openings I should play."
++ Simplest and best is to defend 1 e4 e5 and 1 d4 d5 as black and to open 1 e4 as white.
"some poor moves have a high win rate" ++ Win rate says nothing. When a strong player plays a weak player, he may chose a poor move and still win, especially in fast time controls.
"a4 has a win rate 56%, but e4 has a 36% win rate"
++ 1 a4 has some surprise effect and takes the opponent out of his comfort zone.
"c4 has the highest win rate" ++ 1 c4 often transposes to the same as 1 d4, or 1 Nf3.
"my 3 most common openings have exactly 49% win rate"
++ That says you are matched with equal opponents. A high win rate would indicate you get matched with weaker opponents. A low win rate would indicate you get matched with stronger opponents. The opening does not matter. You can modify your win rate by modifying the rating range of the opponents you seek.
"the Roy Lopez, Berlin Defense probably has lots of theory to memorize."
++ No, the Ruy Lopez Berlin Defence has no theory to memorize. You have to play chess well for it. White gets the better pawn structure, black gets the bishop's pair. It takes skill and experience to utilise the advantage and to mitigate the disadvantage. On the contrary the Ruy Lopez Marshall Attack needs you to know more: it is that sharp, that both sides play on the edge between winning and losing, though with best moves it still draws.
I was wondering what openings I should play.
I have heard that you should look at masters play, but some low rated games are in the chess.com master’s database. I am wondering if this is good advice to follow because some poor moves have a high win rate. For example, a4 has a win rate 56%, but e4 has a 36% win rate.
On lichess, when I select games from all ratings and longer time controls it says c4 has the highest win rate (much better).
I could also use what games I play the best at, but I have only played a few openings many times. For example, my 3 most common openings have exactly 49% win rate.
I could use what engines reccomend, but the Roy Lopez, Berlin Defense probably has lots of theory to memorize.
I would appreciate any help!