As others have said, no because Google’s components have very good backward compatibility and will come for your device on its stock OS.
I had other vendors in mind when I first read your question. In a sense, older ones could spy less as a side effect of vendor telemetry servers going dark over the years. Samsung also wasn’t as rampant with their spying back then. But either way, such phones would have been long without any security updates.





For anonymity alone, no. You ought to at least aspire to live the nomad lifestyle first and put up with its challenges, then enjoy whatever anonymity comes from it as a bonus.
If you don’t mind apartment living, you could consider the arrangement I had at one point. Private landlord who didn’t run background checks, accepted payment in any reasonable form, many tenants, communal mailbox without apartment numbers or names required. Internet, utilities, etc. all rolled into rent and not individually metered. Might be harder to find but they exist.