Actually, I chose LFS. I was building out a systemd-based LFS system, and I had fucked up on GPT vs MBR or something like that, so I binned it. That was like ten hours down the drain, and I felt discouraged, so I didn't retry LFS.
I wanted to avoid the monolithic desktop environments and build one out of individual components that I would then customize to my liking. I had some experience with two 'highly customizable' distributions: Gentoo and Arch. I picked the one that was less likely to get me made fun of /s
It has worked out pretty well. My desktop has some quirks and I want to re-do it, but I haven't gotten around to it yet. Current desktop works and is 'good enough'
Another consideration was the Arch wiki. There are few better resources for getting Linux desktop software to work the way you want it, IMO
IMO using Arch on servers is pointless. It's good for devices you use daily and can take care of regularly - updates are mostly painless then, but once you stop you're simply asking for a lot of additional maintenance burden when you get back to it.
Valve chose SteamOS for the Steam Deck. It is (currently) based on a snapshot of Arch, but deviates so much that it's a huge stretch to still call it Arch. You could just as well say that a device runs Debian when it actually runs Ubuntu.