I haven't tried pedaling 165 mm, I don't know how much worse is uphille and better dowhill in avoiding strikes: bb height of 831 is 344 mm, so means 159 mm clearance with 175 mm cranks and 10 mm sag; using 165 mm cranks will increase it to 169 mm, that is just 7% higher / better.
In my opinion working on suspension sag and hydraulics is the first move to limit dive and then the risk of strikes, but the low BB is part of the so called modern geometry, giving low center of gravity and then of course more stability; I admit I was tempted by 170 mm cranks (santa cruz hightower uses 170 mm), but I never considered 165 mm.
Just a note: the frame is new and we are like beta testers, but the communication with Haideli (Eddy & Joy) so far is excellent, so this is for sure an added value in the choice of buying one frame rather than the other; a lot of aliexpress or chinese companies are just resellers and don't have any technical support.