On Android (13) you can delete the advertising ID under Security & Privacy > More privacy settings > Ads
If it's a public place and you have legitimate business starting there for a while, I don't see any issue with it. Eg. Doctors waiting room and you have an appointment, restaurant and you're dining there, etc.
If it's someone's private home I'd ask first.
I only upgrade every 3-4 years, but there's a lot of subtle differences that make it worth it. For example my current phone is far more reliable with Bluetooth connections than the previous one. It's got a better camera with AI photo touching. It's waterproof. Its fingering sensor is more sensitive and quicker.
If Threads wasn't Threads and wasn't part of the Meta ecosystem, and this could be guaranteed to me forever, sure I might use whatever that would be. But that's so far from reality as to be a meaningless question.