I am using Ubuntu Budgie v20.04.1
Vimix, Ant & other few built-in themes do not support transparent topbar & snap & flatpak.
Yes I know, I have to install those themes in flatpak but still its not respecting them.
Whenever I try to change theme from Budgie Desktop Settings & then reopen Budgie Desktop Settings, it reset the theme, icons, cursor, etc.
Material Design (Adapta) has no icon pack or maybe broken so it crash sometime.
Top Panel Section, I reduce the icon size to 32 but after few time it reset to 39.