Replace your battery.

You would be better off getting an 8 or a 9, as they are already fully supported (by custom ROMs) and will be for at least another 5 - 6 years.

The Pixel devices certainly lost some of their appeal lately with Google cutting down on the superb GrapheneOS support we had up until now. And they're now missing the device-trees and so on and more recently Google has shifted development to not be transparent to the public any more until a new version gets properly released. So updates will be more difficult and won't happen as instantly as we had them in the past.

Google is enshittifying Pixel and Android with noone poised to stop them, so it's a bet where the odds of a getting a good long-term experience are stacked against you.

Would you consider a different manufacturer with less user-hostile behaviour, like Fairphone or Shift?

Fwiw your old op6 will make a mighty fine server

If they don't get device trees for the Pixel 10, it's probably not going to happen. Get a 9 of some variety and see what happens in the next few years. I don't think the 10 is enough of an upgrade to deal with Google's Android that won't allow sideloading in a few months.

I keep writing about Nothing Phones because I got one two months ago (3a) and I am very happy on how lightweight the stock OS is, very similar to the AOSP experience, and the bootloader is unlockable without even asking for permission.

Lineage usually is also supported, but currently not yet on the 3a.

It's a bit bulky.