There's a saying about golf that probably applies to chess: The best way to improve is to go back in time and learn it at an earlier age.
Similarly, it's probably not a coincidence that the best F1 driver happens to be the one who started driving karts the earliest (4 years old) and spent the most time doing it out of even all those elite ones.
This is a story of how one became better golf player by increasing his strength: https://www.youtube.com/watch?v=sr2pgBTRpK4
One can enhance cognitive functions by strength training: https://pmc.ncbi.nlm.nih.gov/articles/PMC8534220/
Aside from time travel, the best way to improve in very important things is through strength training.