Have you tried Chocolatey? https://chocolatey.org/. It's a package manager for Windows and works great, much like brew for Mac. Or, if you prefer portable installation of programs without requiring admin, try Scoop (https://scoop.sh/). Of course, I'd rather use paru or yay on Arch, but I'm glad these options exist.
I find it hilarious that Microsoft even suggests these tools on their own GitHub page for the Windows Terminal.
Thin clients! I "upgraded" from a RPi3 to an HP T630 that I got new off of eBay for $65, including power supply (and case). I was able to upgrade the M.2 storage easily. I use mine as a home server running over a dozen Docker containers. It's x86 instead of ARM too.
The only bad part was installing Linux. It took a while for me to figure out where the UEFI expected the boot files and documentation isn't great.
Can you try pressing ctrl+shift+f2 from within Kitty and then adding font_size 20.0? That will make sure you are editing the same config file Kitty is using.
If that doesn't work, I'd try deleting the config and then try again. Kitty should automatically create a new config.
Since nobody else said it: make sure you have backups of any data you don't want to lose. It's really easy to accidentally partition any connected drive and wipe your data on it. (Learned it the hard way, but at least I had backups.)