I only use it for Whatsapp, bathroom break HN and a few calls a week. Everything else I do from my PC. Also, performance is great for me, I'm not planning on running games or k8s on my mobile.
EDIT: looks like you're talking about the 13 mini, I got the 12 mini, which IIRC has similar battery life complaints. Not sure if it got worse with the latest iteration.
That being said, I also play golf and use a Golf GPS tracker, Pokemon Go, and social media most of the day. Coming from an iPhone 11 Pro which had incredible battery life, it is a major change. BUT, the lower battery life is manageable. I have external battery packs, I prepare for these types of things. I can make it last when I need it to.
I've never heard anyone complain about the performance of the 13 mini before, maybe there's something funky going on with the OP's phone.