I use an 6S that I bought in 2016. It is on its 4th battery replacement. So I've got almost a full 7 years out of it. It won't receive any major iOS updates any

I use an 6S that I bought in 2016. It is on its 4th battery replacement. So I've got almost a full 7 years out of it. It won't receive any major iOS updates anymore, but will still receive security updates. I'd continue down this path for another 2 years, but as a non-iCloud user I want iCloud Advanced Data Protection to sync Notes and Messages.