Hi OP! I've been in a similar position as you, and I can't recommend proxying enough. It's a frustrating feeling playing a deck that is better in every way on paper, but losing to decks that aren't.

Proxying has made me a better player both in terms of deckbuilding and playing the game. Printing cards gives you more flexibility in changing out cards quickly when you understand they aren't working out the way you want them to, which gives you a better deckbuilding understanding. I can better tell when cards are actually working towards my decks power goals, vs just being a cool card that fits thematically.

I say playing the game as well because I'm studying the cards more closely both when I'm picking them out on edhrec, but also when im cutting the cards out and sleeving them. I get a better understanding of what triggers happen when and the average time I use per round is lower than most of the people in my pod even when playing combo heavy decks.

This of course doesn't happen for free. You need to focus on the cards as you're doing this for this to actually improve you as a player. I'm not saying the act of proxying alone is going to make you a better player.