What if some mysticism gets introduced?
The armorer claims to be able to see it in one’s eyes if a person has actually encountered a Mythosaur. So she invites Bo Katan to take off her Helmet, but warns her that she will be killed if she has lied about the Mythosaur thing.
“The true leader of Mandalore will forge a an alliance of all our people… chosen by the mighty Mythosaur itself”
“Encountering the Mythosaur leaves a mark. You can see it in the eyes of a Mandalorian. So if you want to proof your claim, remove your helmet. Should you have Lied, death will be your reward, as is our custom”
I think this would be nicely fitting with Bo Katans attitude when removing her Helmet.