Hi all, I am getting a lot of lines on my FPV cam of my new build probably from motor vibration because on my second flying session, 3 motor screws of the same motor came off. This I can solve with threadlock but it is a further indication of motor vibration. I am using the EMAX red bottoms 2205 2300 steel shaft. Would soft mounting help? And is there anything else I can do? Thanks!

Genuine emax motors should not have vibration for a new build.
Soft mounting might help. Use threadlock, tighten them firmly, and try again with good props.
Also make sure to tune your PID!

It's unlikely that vibration would cause lines in your video. Video interference is normally electrical in nature.

Things you can do to get rid of interference are:

Use an LC filter to clean the power you feed to the camera and VTX.
Make sure that both the camera and VTX share a common ground.
Twist video and ground signal wires together.
Do not route video signal cables near your ESCs or PDB.

Without knowing what craft, camera, VTX and how you have everything connected, it's hard to offer anything else than generic advice.

If you have lots of vibration from your motors, the first thing you should do is check your propellers. Damaged propellers will cause vibration. Some propellers are horribly out of balance, even when new and need balancing to get rid of vibration.

Always use blue thread lock when mounting motors! In fact, any screw that screws into a metal thread should be locked as they will inevitably come loose sooner or later.