

I suspect the tricky part will be what to do if the alt account’s server doesn’t have a federated copy of the content. In that case, going to the home feed would be fine, perhaps with a notification giving the option to open the content in web. Maybe also return to the content/where you left off when switching back to the original account.
Yes, that would be a concern, which is why I’d prefer this to be an option, ideally defaulted to the current behavior. That way, if someone wants to be sure their alt acct doesn’t potentially leak to instance admins, they can leave the feature off.