On the solid infill, well short answer is also you cant.  Longer answer is you sort of can but it requires use of modifiers.

The solid infill pattern used to just be regular cross hatched pattern until a few versions ago.  Then they changed it to its current behaviour.  Its to reduce violent shaking on small areas amongst other things.

There have been several posts here and on the github about this.   For example https://github.com/prusa3d/PrusaSlicer/issues/10573  

For the infill with modifiers you can read https://github.com/prusa3d/PrusaSlicer/issues/13563  

Same with requests to change the function - https://github.com/prusa3d/PrusaSlicer/issues/2147 (that one from 2019)

SOLID INFILL (adjacent to topmost layer)

TOP INFILL

The concentric pattern in the solid infill seems to only happen on thin elements. The issue is that this pattern is causing overextusion in the centre of the pattern. I'd like to fix the problem:

1) by minimizing the overextrusion caused by the concentric pattern or
2) by applying the top infill pattern to the solid infill instead. 

Any help is appreciated!