My own experience.

Almost not one day not thinking back, always regret a lot. What if? Then I tell myself most likely the same. Adults can hardly change, especially for a stubborn one like myself.

Then I tell myself, instead of gloom and regret, better use more positive energy on remained family members, esp those around .

I noticed during recent SH lockdown, may elderly live alone, SH is more and more like west.

So if one parent still alive, make remedy now, see /talk more often.