Minor stuff
https://imgur.com/a/DJDaQNZ

wow, good job! thank you, i will fix those bug. picture #9 and #10 aren't fixable. these are "autocombine" models (its one big model).

#4: i clipped the stairs, but the angle was too steep to climb. i'm not sure if i can fix that. thats the reason why the stairs are not clipped.

Ya, I almost thought they were autocombine.
The stairs is tricky, it is all one model right? You could perhaps scale it up a bit and let the remaining part be hidden underground, but then you would have to make the stairs stick out a bit at the bottom. By doing this, you would probably get a less steep angle so that it is walkable.
Not sure if you would want to do that though, like the red line in the image in opposite to the green which is the current one.
https://imgur.com/D0XV6DS

Or you could just keep it like it is, I guess it works =)

the stairs consists of 5 or 6 parts. i've tried the same way like on your picture, but you have to raise the angle very much. that wouldn' look good :(

Bro at the B bridge (now wooden one) there is a tree and how to say it is only visual bots can see through this and bullet passing like nothing hope u understand

Not a bug, but the walls at bridges look odd, one near site is so white and the other one so mossy. You can paint some moss onto the white wall.

Helicopter is shown twice, one low at ct spawn and one very high up in the sky

The helicopter at ct spawn clips through a tree behind the spawn point, hope you can fix it.
and there is a little "Pecklesteiner" in every door

a gap between the ramp and wall that goes up towards b site
https://imgur.com/gallery/Kg3OJDt

https://ibb.co/CQSvM0k
https://ibb.co/17dRwwH
https://ibb.co/vc7ZHJv
https://ibb.co/0yfhFHn
Some floating rocks, hopes these are fixable.

thank you guys, i will take a look at it.

nice 0 bugs

https://imgur.com/a/72Joe9P weird clippings i found