There's a few portions I'd like to address here, so here's my bulleted list:
- First of all, welcome back to chess and chess.com
- The next part I'd like to answer is when you ask "What's the best way to come back to chess...?" The answer is that you taking a break from chess or not doesn't actually change how you learn chess. If you were working on chess everyday or if you were taking a hiatus from chess, then in each case you improve by working on your chess. This means analyzing your own chess games to learn from your mistakes, solving chess puzzles, studying basic checkmates and theoretical endgames and so forth.
- The "anxiety" part is the main thing holding you back here, but I appreciate the openness and honestly in sharing what you have. I'm all for longer time controls and giving yourself enough time to not feel rushed in your games, but this is obviously not healthy long-term if done to avoid (or "very apprehensive about") "playing other matches."
Chess is not about rating and numbers. If you want long-term improvement, then it is about learning and increasing your overall chess ability and level of chess understanding. If you do this, then your rating will naturally go up and catch up to you. It is good to value rating and care about it a little, but it is not good to obsess over the numbers and feel apprehensive about playing. Losing is part of the learning process. Variance is a mathematical concept and there is no way around it. Variance can sometimes be minimized, but you can't eliminate it entirely (you also might not necessarily want to lower variance at all, but that's a different and more complex topic).
I recognize that this video of mine is almost an hour long, but it is really important information and I recommend checking it out. I believe that this can help you. Your "anxiety" of resorting to 15/10 (and later taking a 2 year break) sounds like the start of my "What does NOT work" section just a few minutes into the video; quitting is not a cure.
Think of the information in this video as an investment. You invest an hour of your time to learn these things, but even if it helps you win just 2 chess games, then it was time well spent. 15/10 time control probably takes about half an hour to complete (15 min per player plus the increment), so winning 2 games (and not having to spend time gaining back lost rating) gives you a net gain on your time.
If you want a shorter video which is entertaining (and something more recent from me), then later you can watch a video like this Tal game which really impressed me
I began learning chess in early 2021, though would only really get into it in late 2022, where I would play a lot, as well as putting a lot of work into getting better at it (Watching videos, learning openings, recognizing patterns, etc).
Doing that, I managed to get to 900 Elo (Though one of my regrets was always taking way too much time every game, having o resort to 15 | 10 instead of 10 minute rapids so I didn't flag a lot of my games), but I stopped mainly due to "anxiety" (I know it's irrational, but I had adrenaline rushes doing games, and after every win I felt very apprehensive about playing other matches).
Recently I felt like going back and solving the issues I had two years ago, though I feel that I forgot much that I knew back then, what would be the best way to "get back in"? Can I use my forgetfulness as an advantage in order to re-learn things without certain vices I had?