Most mods don't even touch the rendering system, they just supply models in json format. If you do need custom rendering, Minecraft has the Blaze3D api, and that should be mostly unchanged. There are relatively few mods like Sodium and Iris that make extensive use of direct opengl calls.
Rich people aren't the only ones that want to hide their address. Stalking/DV victims can use this too, or even just a regular person that prefers privacy.
I have not used quadlets in a "real" production environment but deploying systemd services is very easy to automate with something like Ansible.
But I don't see this as a replacement for k8s as a platform for generic applications, more for deploying a specific set of containers to a fleet of servers with less overhead and complexity.
There are actually two versions of the Curseforge client, the "Overwolf" version that is built on that platform (and is quite bad as a result) and a newer standalone version that doesn't use Overwolf, it's much better.
Main difference for NeoForge developers will be method parameter names in the IDE, the current mapping doesn't include those. We have community mappings (Parchment) for common methods, but there are a lot of less used functions that just have decompiler names. I don't use Fabric so I'm not sure how it will affect those devs.