Not sure if relevant, I see you’ve incorporated procedural mesh for the grid. Not 100% what the intent is but if the plan is to create actual tiles to move on, consider a HISM:
It works with navmesh:
Just a thought, perhaps not applicable - my understanding of the final goal is somewhat fuzzy. Perhaps you want to design the adventure map in Notepad 
and import it 
If you’re after something more exciting, like procedural generation, do look into Wave Function Collapse - it’s a general concept that yields pretty good results.