If you do have something like a Pixel / Galaxy already, consider installing DuckDuckGo browser. It's not just a browser... it also runs an onboard vpn, which has the side effect of blocking ad tracking requests. I was kinda horrified and surprised to see what kind of info most of the apps were taking, and how often they were making the requests. GPS (both coarse & fine), IMEI, post code, email address, all kinds of other identifiers.

You'll have to manually let a few apps through (stuff like the wallet, maybe banking apps) but everything else is blocked on my phone.

If I was going to buy a new smartphone right now, I'd prob get a Fairphone:

Fairphone is a Dutch electronics manufacturer that designs and produces smartphones and headphones. It aims to minimise the ethical and environmental impact of its devices by using recycled, fairtrade and conflict-free materials, maintaining fair labour conditions throughout its workforce and suppliers, and enabling users to easily repair their devices through modular design and by providing replacement parts