Well, Android is a mess, that’s for sure, as is basically the whole software industry nowadays … what else is new … but this data loss still sounds unusual.
What and how do you upgrade exactly?
You might want to have a look at UBports (ex Ubuntu Touch) … but I think it’s not daily driver ready yet. Here’s what the forum says so far.
And from your comments here I guess you will not like their fancy installer (which looks nice, but doesn’t work reliably yet), but here’s an alternative way to install, which works.
Do we need that many Linux distributions? We need one which works 
.