Reply To: One object I can’t get rid of stretching on

I don’t see red:

(tried it in 2.83, 2.92 and 2.93…)

However, you haven’t Applied the Scale on a few pieces:

Apply the Scale, select All (not in Local Mode!) and Unwrap again.

Then select All in the UV-Editor and Average Island Scale, Pack Islands.

If something still  shows red, ignore it, the only stretching is at the corners of the rim:

(Which, in this case wouldn’t even be a major issue…)