Really? I find that on MacOS apps are very inconsistent about whether popping open a menu shows me hints for selecting items in that menu. Those same apps are consistent about it on Linux.
And then there's the bonkers window manager which can't move focus directionally (e.g. Super + left) and so you have to fall back to Cmd + tab tab tab tab but even then there's no consistency about whether you're switching between app instances or windows instances within the same app...
Display of shortcuts in menus is the responsibility of the app developer (especially in the case of use of foreign UI toolkits). If you don’t see them it’s because its dev dropped the ball and the Mac version is an afterthought.