The way I see it, either The Child storyline gets wrapped up this season, and the show continues with a new quest alongside the bigger Mandalorians storyline, or it somehow takes 4 seasons to find a resolution for The Child and this happens around the same time that Bo-Katan retakes Mandalore.
I definitely think the inclusion of Bo Katan is the first step in a buildup towards a much wider scope in future seasons where the planet Mandalore itself will be involved. But this season is doing such a great job of portraying Mando and the child as a lovable duo and inseparable pair, I can’t see Din actually leaving him behind, but I’ve no idea how else it would work out.
However, they’ve setup a really interesting future conflict. Someday, Bo-Katan will be in the same room as The Armourer, and both of them will be claiming to be the true and rightful keeper of The Way. When that time comes, which side will Mando choose?
I bet Din is very bitter towards the Armourer right now for suggesting there is only one way to be a Mandalorian. It’s clear he had no idea he was part of a cult, and now he’s realising that Mandalorian armour is earned, instead of it being a birthright.