Your old self isn’t your enemy. They were just running on a weaker charger.

The person you were had less information, less support and fewer tools, and made decisions inside those limits. Treating them as an idiot is both unfair and useless, since they are the reason you know anything now. Most regret is really hindsight applied to someone who did not have it. They were doing the best available with what was plugged in.

The next time an old memory makes you wince, add the context out loud: what you knew then, who was around, how tired you were. Say what that version got right, even if it is small. Then use the energy for something the current version can change.