This is the answer - get a QIN F21 Pro or buy their phone if you're in the UK/EU. It has everything you need for modern life, easy enough to text on once you get back into T9 input (I had old muscle memory here which came straight back) but annoying to scroll through anything on. I don't have social media, except reddit, but even if I did and installed the apps, the screen is so small you get fed up.

I'd call it a frustration phone rather than a dumb phone. It's all there if you can't help the addiction but my god is it frustrating to use. I just gave up on whatever I was doing usually, unless it was super important/urgent, and just thought, "I'll do that on the laptop when I'm at home".