A Minecraft 1.20.1 profile can remain useful for established mod collections and servers, but it must use a ViaFabricPlus build that explicitly supports the same environment. Compatibility is a profile-wide decision, not a filename guess.
Build the profile around Minecraft 1.20.1
Select Minecraft 1.20.1 first, then choose a compatible Fabric Loader and dependencies. Avoid mixing files copied from a newer profile because they may target different APIs or mapping expectations.
Check networking mod overlap
Mods that alter protocol handling, server lists, connection screens, or packets can overlap with ViaFabricPlus. Begin with one networking solution and add alternatives only after the base profile is stable.
Use a controlled server test
Test one server at a time and record the protocol setting used. If one server works and another does not, the difference may be server configuration rather than a broken client installation.
Diagnose launch errors
A loader error often identifies the missing or incompatible component. Read the earliest meaningful message, remove duplicate versions, and avoid adding a second copy with a slightly different filename.
Keep 1.20.1 separate from newer branches
Do not share one mods folder between 1.20.1 and 1.21.4 profiles. Separate folders prevent accidental cross-version loading and make updates safer.