Nah man, iPhones will last even longer than that. Swap the battery when it hits the 78% health mark and keep on trucking.
Mine is over 5 years old now and after considering upgrading, I just decided to buy a new battery and replace it. Much easier than most people realize but I have been fixing them for like 18 years now so maybe I’m biased.
I keep friends and family iPhones going until they just simply want to upgrade, not because of planned obsolescence or incompatibility. The former typically happens first…