@Tobias, thanks for looking into this! Note, please, this was not another general card sharing request: this is just a way to refer a card from outside of SN for my own (owner) purposes.
Use case: there are several cards, which may need my further attention at the specific time in the future. As there are no means in SN to let a card show some kind of notification at a given time I wanted to put a link to the card in a system reminder or calendar. This is why I wanted to create a link.
BTW, internal link syntax (https://my.supernotes.app/view/home/%a5003472-5199-4b69-8dd9-eb459e7ffd39) does not work as well: it shows blank page when you put it in the address field and press Enter.