NavMeshes and Tight Spaces

I’ve recently started to work with NavMeshes and I’ve run into a snag trying to get it to cooperate with tight places, especially doors. Specifically, this gate here:

The collision doesn’t block the inside, as far as I can tell:

I spent quite some time playing with the settings on the RecastNavMesh-Default, trying different cell sized and heights (even going down to 1), as well as agent heights and radii (again, even going down to 1), but I simply could not find any config whatsoever that would allow my NPCs to walk through this gate. Now, the gate is relatively small, the outside width is slightly wider than the basic cube, which is 1 UE I think, so that’d explain why the NavMesh even at cell size 1 can’t go through it and why a character can thus never find a away through it. Or at least that’s my assumption.
While digging around I found some mentions of NavLinks and an old training video. I haven’t started on these yet, but I’m curious: Is this really how it should be done? Any somewhat tight space like a door or even a tighter squeeze for a smaller creature has to be connected through NavLinks? Or is there something I’m missing?