Weird. I guess Shotcut performs better on low level machines when running Linux. Case and point (and this has a LOT of keyframing):
So I guess you will have to invest in more RAM if you want to avoid these problems, which isn’t very expensive these days and is probably easier than moving to a different OS.
Incidentally, how is your virtual memory configured?
On programs that can occasionally hog memory (like Photoshop) some users have reported setting an InitialSize AND MaximumSize to the same number - like 20Gb - has helped. The below suggests video editing apps perform best with a large page file so try that.