LFS is just on a whole different level, and is on my bucket list to complete the entire process one day.
Like, yes you get pretty familiar with autotools, sed, and patch. However, a lot of LFS is in fact just managing disk partitions and moving files around.
LFS also glosses over a lot of pretty important parts like kernel configuration.
The docs from both Gentoo and Arch, on the other hand, are much more complete and practical in explaining things and also troubleshooting problems. And at the end of the process you're left with a system that can be easily maintained.
LFS is harder, but that doesn't really mean you end up learning more. Especially since it's pretty easy to lose focus and just rely on copy/pasting the next command to run.
Edit: Just an example of what I mean.
Here is the LFS discussion of filesystems.
https://www.linuxfromscratch.org/lfs/view/stable/chapter02/c...
And here is the same Gentoo discussion.
https://wiki.gentoo.org/wiki/Handbook:AMD64/Installation/Dis...
That's where you end up learning a lot about linux which is particularly practical. Other Linux distros, especially for the desktop, hide a lot of this information behind nice guis.
[1] https://wiki.archlinux.org/title/General_recommendations
As an addendum, you have to do it for your actual working computer, otherwise, doing it on a VM or a machine you don't use, you won't be learning nearly as much as there is no pressure to make it truly work for you (this is where learning happens, when the thing you wanted to configure, and LFS docs or web docs are out of date on, so you have to dig deeper).