Custom Inbox folder label can't be removed from messages

Hello, in order to work around Gmail Categories Support - #6 by system, I’ve set up one of my gmail accounts to assign labels using a filter. I’m hoping to make the label that corresponds to the primary tab correspond to the Inbox for this account, so that not all the messages in all the categories show up by default in the “All Inboxes” view or in the “Inbox” view for this account. For simplicity’s sake, let’s say the filter labels Primary messages as “Primary”.

I set the custom inbox as in this screenshot:

And then it seems to work.

However, it now becomes impossible to remove this label to get the messages out of my pseudo-Inbox.

Clicking on the X on the label pops up the notification on the lower right of the image (sorry had to combine to one bc of new user image limit)
SS4

but doesn’t actually remove the label. The message retains the label. It can be removed in the gmail interface, but not in Mailspring; the label doesn’t even show up in the label menu, as populated in Mailspring, to remove manually.

Any ideas on how to do this?

Importantly, I don’t actually care about having the ability to remove a label that “=” the custom inbox, if there is another way just to make my inbox only show messages that match a certain gmail category, as the default inbox. But if the only way to do this is through this workaround, then I would indeed be grateful to know if there is a way to remove the label that is also used as the custom inbox from a message in said “inbox.”

Thank you