When such a universal program will open video files with the H.265 codec, which is the basis for recording car video recorders. Without this codec, the program is rubbish and old, not worth buying. Money thrown away.
Even H.264 isn't mentioned as being supported (although I will concede that it says "Supports smartphone, action cam and digicam videos"). This is obviously incorrect, and you should take that up with Ashampoo, as the seller.
If you would like to resolve the problem by using a free app to convert your H.265 footage to H.264 which I believe Video Easy can handle, download and install Handbrake. Yes, it does mean an extra step in your editing process but, as @AAProds has pointed out, that Magix web page shows that H.265 is not supported.
I bought the product from the ashampoo offer, which I received by e-mail. There was no information on the offer page that the program did not support the H.265 codec.