I regretted paying the 100€ cause the issue seems to have been software related. If I had done the software reset before the battery swap I'd theoretically get a good enough battery life that I wouldn't consider the swap.
Buying the 14 pro max is unrelated to the apple store experience but it was the best solution for me in the end.
I replaced the battery of my iPhone 12 mini and I regret it. The battery health was at 83% but the phone wouldn't last 4 hours (not screen on time just 4 hours period).
I asked apple if this is expected and they said no and that my battery cycles where high enough where a replacement would make sense. I did the update, paid 100€ for it and the battery life went from 4 hours to 8 hours...
I took the phone back to them and after another look they suggested me to do a fancy factory reset while connected to a mac and without restoring from a backup. Lo and behold the phone went back to normal battery use and is now usable again.
Anyways, I didn't want that stress in my life so I went with an iPhone 14 pro max and now battery is not an issue anymore.
Loving the app btw :)
How can touch be real if our lips don't touch when we say it?
Thank you everyone for your suggestions. I think I'll go with eldar or tau as I like their minis and the lore too.