Is there a way I can manually add a Mac app to an item's Linked Apps other than via Quick Access?

Not sure if my problem is related but I also need a way to link apps manually or to override the default behaviour when an app is linked. I have multiple Microsoft accounts for example and when one of them is linked that one is always used to login. I can never select another account. So the current workaround is to remove the linked app from the first account and then 'm given the dropdown again to select the correct item.
In short the whole linked app feature is useless if you have multiple accounts for the same website. Hope this helps investigate and probably solve this.