Another Ngon question

How do I model around using Ngons in these type of positions? Once I add a bevel and a sub-div it goes ham.

Do I need to always try and retopo those corners in such a way that they always only have four edges? How would adding a triangle, like in the second picture affect my flow?

I’m not sure, what exactly you are doing here. Setting crease to 1 for all hard edges and use subdiv to smooth the cylinder? In any case, interesting problem. I don’t have a real answer on what the perfect topo should be here, but what I find is that for the bevel operation changing the Outer Miter Type from Sharp to Patch or Arc gives a topo which behaves nice with subdiv.

I would add a control loop:

Yeah, sud div for the cylinder, and then adding a bevel for the edges.