I fully second the sentiment that there is no good reason to switch distribution once you have found one that you like.

However, if your goal is to learn something new, and you don’t care about having to nuke the install and start over, then you could go the crazy route and install Linux From Scratch. It is unlikely to yield a maintainable result at first try, but if learning is your goal, this is your best shot at it.

Or you could go the not-that-crazy route and use Gentoo, which is basically Linux From Scratch, but automated. Setting it up is way quicker (couple of hours - except if you configure the kernel by hand), and you will with near certainty get a maintainable system on first try, but it is also far less educational, given that the automation does most of the work for you. (I have switched from Debian to Gentoo 10 years ago, after trying it on my netbook for some time, and I could not be happier. It only does what it should, is rolling release, and only very rarely has issues.)

I would only recommend those two approaches on a second PC though, without immediately switching the main PC over. Linux From Scratch is, as said, unlikely to yield a maintainable installation on first try, so you will likely nuke the install again. Gentoo, while perfectly usable as a daily driver, is certainly not everyone’s beer, and you might simply want to switch away again because you don’t like it.