mac builds require a lot of things, things that we don't really focus on when in our firsts games
Viewing post in FloraLumina jam comments
Mac builds require 1-2 more fields to be filled. Nobody expects the developers in a game jam to upload a signed/notarized build. Since accessibility is an important part in the GWJ, they put rule 6 in there. Its a few clicks more in the export - I get that this can be overwhelming for beginners, but its also valuable knowledge.
no, you don't actually need a mac to do mac exports. After you've downloaded the export templates, you can just add mac as an option in the export window.
Check this out: https://docs.godotengine.org/en/stable/tutorials/export/exporting_for_macos.html