Heres a couple issues im haveing

1.Sometimes enemys dont spawn at all in certain vanilla maps (I built a epic base but no AI ever attacked)

2. Enemys mostly come in groups of 2 so things get boreing real fast (For some reason they come in more groups in survival but not skrimish defence)

Any way i can fix this these are the only issues that ruin parts of the game for me

1. When you build a huge base with many actors, you probably reach the MOID limit; this means that there can't exist additional movable objects, hence the non-spawned enemies. To fix this, just build simpler bases with less guards.

2. I think this can be because either A) You placed too many actors, like in point 1, but there is still room for one or two to get spawned or B) You lowered the difficulty.

I hope this helps!

Is being around 255 or 250 the limit? if so the limit really needs to be higher

The limit is 255. There was some talk of the possibility of it being removed so one can hope.