I had a very similar experience doing this too. Lost about 21kg in 2-3 months and went from 98kg to 77 kg in 3 months which is a lot for a guy who is 5'7. 16/8 IF(Intermittent fasting) , mostly plant based and one day was a cheat day.Didn't exersise at all for the majority of that period and even when I did the intensity wasn't high enough to put a dent in caloric deficit coming for eating less.
I did this 5 years ago and am still doing it and haven't gained my weight back. But I'll say that retaining my weight is harder now.I was 22 when I did that and stabilized at 71/72 kg for couple of years but now at 27 I am stable at 76/77 kg.Although exercising more and maybe having gained some muscle mass might account for that extra weight.My body fat percentage (assessing only visually) seems lowest than it has ever been.
With regards to the children argument I have largely seen the opposite where the parents directly/indirectly confess that they to a large degree regret having kids in their 30s /20s and would have rather globetrotted or did their own version of their pursuit of happiness.
My point is not that children are the source of the problem but that these things about what you would rather do is personal to each human.I don't think one can make a blanket statement about rasing kids or doing you thing as there are quite many people on either side who regret the path that they have taken.
Also your bond with your parents is quite heartwarming and I hope you od realize how lucky you are to have that.
That's the weird thing about meaning it is completely subjective to that person.Having better connections with people especially one's immediate family and friends ,doing something that helps something larger you (like your pwd manager),etc has a good chance but does not gurantee meaning in one's life.
Overcoming a challenge which is hard (but within your limits a hard) is an incredible thing to experience.
As we humans are social creatures something emotional(mostly +ve) might also sustain your involvement in that activity and thus lead to eventual higher reward from that activity.
But at the end for most people who are present here I think I can safely say that doing something which involves less screen time and more "physical interaction" with the world would be beneficial.
I did this 5 years ago and am still doing it and haven't gained my weight back. But I'll say that retaining my weight is harder now.I was 22 when I did that and stabilized at 71/72 kg for couple of years but now at 27 I am stable at 76/77 kg.Although exercising more and maybe having gained some muscle mass might account for that extra weight.My body fat percentage (assessing only visually) seems lowest than it has ever been.