Tab Groups shortcuts in Safari are not working

I have a problem with the keyboard shortcut SHIFT + CMD + Up/Down arrow on Safari. By default, it should go to the next or previous Tab Group. In my case, it scrolls to the bottom/top of the page. Same with CMD + Up/Down arrows.

Also with SHIFT + CMD + Right/Left arrow, it switches between open tabs. So possibly it is overwritten by some app.

(I tried to disable all extensions and quit BetterTouchTool, but issues still persisted)

Can you help me with that? It is possible to find out which app does this?

Thanks a lot for your help.