My phone is slow and I think it's by Google's design. Is there anything I can do about it?

This happened on all android devices I've owned. Once they turn about 3 years old, they start slowing down out of a sudden. Yes, software gets heavier, you need more processing power, etc. But it happens out of a sudden.

I dug out an old lebovo tablet, about 6 years old. It ran surprisingly quickly. As soon as I turned the WiFi on to install the app I needed, things slowed down to the point where the device was barely usable. I somehow installed it. The app didn't require internet access so it was fine. Battery life was still amazing, about 5 days of casual use (internet access drains a lot of battery on this fella).

I thought it was a one time thing. Until I was handed another old Alcatel tablet that was ditched due to slowdown after 3 years. Same thing, no internet access leads to a snappy phone. Once you turn the WiFi on, boom slowdown.

I see the same thing happening to my Nokia 3.4 phone (now HMD Global, made in China). I don't think the architecture allows for swapping the os to a degoogled one everyone is raving about. The reparibility of this phone is near zero so once it goes bust, it's really hard to open it as well. I obviously don't need a brick with no internet access (otherwise I would just carry a dumb phone).

Also once this buddy dies or becomes unusable, is there a brand you would recommend. I'm so done with Nokia and Samsung.