Musicians: Adding your own music to TT in-app vs baked into video edited offline

GOAL: Find the fastest workflow that lets me create shorts that can be used across TT, IG, YT shorts, etc that feature a small looped section of my music (already uploaded to YT Music, TT, etc via Distrokid)

ISSUES: It's my first time doing this, so not sure if I need on TT for instance to use the "add music" button to find my music and add that way, or if I can use a pre-edited section I upload myself that is the exact right loop length.

What are the pros and cons either way? Is there a best way to do this? It would seem much easier to use an external app and automate uploading to all the platforms, so is there a way to do this that is still as fluid to encourage others to make their own videos with my sounds?