The approach I've followed for many years is to have /home mount on a separate partition from anything else. Then when you do any kind of fresh install or upgrade, you only have to make sure that partition doesn't get touched (and usually that's the default) and all is well with the world.

It would be slightly more work involving parted (or whatever partition manager you prefer) to create a new partition, resize existing partitions, etc., but quite doable (if tedious and time consuming).

By clean setup I mean, reinstalling /

/home is kept intact. After installation of apps on new setup I don't even have to configure them most of times because they can find their config directories in /home/myuser/

but debian iirc has only one partition by default, no?

That is not true. I have configured /home on Debian.

I used to keep my home dir on a separate partition, but I was always worried I'd wipe it out during the OS install.

Instead I backup my home dir with borg backup to drives/cloud.

I have a script to borg mount my most recent borg backup, so when I set up a new OS install, I just run the script and copy my files over from my backup to my computer's SSD.

I love this method because I can easily install a different SSD, switch to a new computer, or just do a clean OS installation very easily.