I am on e/OS since 2021 with a FP3 and, for what is worth, I never had to reinstall, wipe or anything. My phone just had it's 5th birthday and it has been a single continuous set of updates.

I know the versions differ by model, so perhaps your model was not as well supported.

It was the gigaset gs190. I've used it quite some time with e/os, but one day the automatic updates stopped working and I discovered this reinstallation requirement.