In 2.92 the menus are slightly different. It took me a while to figure why my normal map had green colours in them. like here.
There’s an extrusion option which I played with and helped me get to this:
A lot more details. This is the menu I’m talking about
looks like you are on the right track, more playing with that extrusion. I suspect it is where your low poly is not matching the high poly very well and it is sticking through.
I didn’t know how the baking process will be exactly so the places where I used the brush are a bit unmatched with the height
