While it's nice this exists on Forge at all, and can be enjoyed with all the various Forge-only mods that were around back then and will never leave for Fabric, there's no getting around the fact that 1.12.2 is about six years old at this point. That's about as much time between us and 1.12 as there was between 1.12 and Beta 1.7.3. At this point, it's only useful for anarchy servers and those most stubborn (or abandoned) mods.

The fabric version can support 1.19, 1.18, and 1.17. Why can't the Forge version?

This was a one-off project for a friend who specifically set up a 1.12.2 server. I'm not looking to do more beyond this.

Fair enough.