Now I wanted it for myself and just made it. So at least I can confirm this works.

Only difference is I don´t actually use the sharesheet much so I do it with clipboard content: Take either screenshot or copy text. Press a shortcut to put it in Anki with a request to AnkiConnect.

Works flawlessly on Mac/Desktop but if you want to do it from mobile devices, you have to muck around with network permissions etc. Too much for this evening.

Easy extension is to make 2 shortcuts for each of back and frontside, then copy twice, then use Keyboard Maestro to call up both shortcuts and fill both front and back sides with the material you need to make the cards.

Thanks for the stimulating question! :)