With each new version of an application there’s the change that configuration files or functionality changes. Packages might even get replaced with others.
Even if this would be true, how would that impact your configuration? It doesn’t full-stop. If you want to access those new features you simply need to check how to activate them in your config file. Or are you making config edits in /etc/ ?!
Your next paragraph I don’t understand, it seems specifically aimed at some kind of self “maintained” script, which as nothing to do with rolling release or distributions.
Uhm you never actually used a rolling release distro obviously. Why would you have to read change logs? Also what are you referring to with “test my documentation (shell scripts)”? Why would those not work if package xyz is updated? You are not making much sense, but maybe I am lacking the experience in UNIX to understand your point of view.
Your package manager should tell you about conflicts and even if it doesn’t and something is not working like it did before, you do a simple snapshot rollback and wait another week to update or actually read what might cause the issue. And those incidents are like super rare, at least on Opensuse Tumbleweed (e.g. 2-3 times in a year).
I don’t understand what it means to "not get moved to backport repos, but this seems ubuntu specific. What you need is proper rollback/snapshot mechanisms in place. Looking at Tumbleweed which offers it out of the box. For Arch you can set it up yourself or use something community made like EndeavourOS.
Iam using Tumbleweed for close to 10 years now and it was pretty mature from the start. You can’t go wrong with rolling release + perfectly configured btrfs + snapper by default.
People think “updates are time consuming” therefore prefer LTS because its supported for longer. I parole for quite some time that LTS has no place for private use and rolling release is the right way.