I am using FreeTube Flatpak and it seems to support Wayland now.
But (maybe coincidental) the Plasma 5.27 Breeze cursor is tiny when hovering over the app, which didnt occur before. Enforcing X11 (XWayland) makes it scale normally.
Under Wayland, each application is in charge of drawing their cursors and if they do something wrong (such as ignoring the desktop scale ratio) then you get annoying behavior like that.
It’s a design bug in Wayland that the Wayland developers refuse to address, so it isn’t likely to be solved (globally) soon, but you can report the issue to the application developer and they should be able to fix it on their side.