Sad? It seems very forceful to me
Killing MC's mother for development?
If you want to stick with canon without the mother being exist, why not kill her when MC was born, with that it won't feel so forceful
I was really happy when you stated in chapter 1 that the system would only be a gacha with inventory. but now... Fuck this... Too many systems with AIs that became MC's nannies and Quests that **** up the story...
Hope you have fun writing but this is it for me...
Author, I can consider that the senzu beans where from another universe of Dragon Ball, because, quoting Dragon Ball wiki "despite their highly rejuvenating nature, they cannot heal people of diseases as it failed to cure Goku's heart virus."