There's lineageOS for outdated pixel device, but I think you loose device attestation if you flash that, so your banking, payment and digital-ID apps won't work anymore which is kind of important features for a lot of people.

I still think separating a phone for phone apps and a PC for productivity, is the best choice even if that PC is a 20 year old rustbucket from the dumpster, it will still do more tasks than a phone. You can't learn photoshop on a phone.