When zoomed out every marker except for banners get smaller. Banners keep the same size they had before.

Version Used: Map Atlases-forge-1.19.2-3.0.1.jar

This has been fixed in newer moonlight versions with direct compatibility with the atlas zoom feature. Once I'm done overhauling the mod I'll backport to 1.19

Also technically it's the banners that get bigger xD