I have the latest of everything. Starlight, Lithium, Tic-Tacs. I still get a pause when going in-between chunk borders. I have starlight server-side and client-side. My server runs on an Intel Xeon, so I don't think hardware is the issue. My server also has 8gb of ram, which is plenty enough for twenty players total (only 1-4 on at a time).

I wish I could give you the video evidence, but it is larger than 10MB ):

It does get very annoying during elytra flight. It isn't high priority, as the game is still playable. It is just one of those quality of life things.

From the performance numbers I've seen locally, in my experience it's actually just the rendering of these new chunks being loaded in that's causing spikes. While I want to fix issues like these, if it's not caused by the lightengine I really can't do anything from starlight.