Thanks people
I decided to go for FX2D (after running the code in Launcher for Multi-Renderer PApplets).
It seems to solve all problems with regards to size.
Here are some notes from my code
/*
Selecting the renderer
1.
Default rendering screws me around with windows scaling
2
P2D is OK but maximizing window takes long and circle first changes to ellipse and next to circle when maximizing
Ignores windows scaling :+1:
Places (in left top) without title bar :(
Seems to have jaggered edges around cirles.
3
FX2D does not (easily) allow to align text (vertical align in circle)
Needs trick to suppress windows scaling; that's acceptable
*/
I haven’t found the best way to sort the vertical text alignment out, for now subtract a fixed amount. There was a similar issue in Processing 4.2 that got solved in 4.3; see Processing 4.3 is out! ✨ - #3 by sterretje.
This leaves the first question why there is a difference between Processing 4.3 and the later versions with regards to the default renderer. I know that there is a difference in the java version (checked by running Report System and Environment Diagnostics at Runtime) but I do not know if that is the cause.