Is it safe to out a screen protector and keyboard cover on the new MacBook Pro 2020?

Either can damage the display which costs between US$500 and 650 to replace. It is your decision but I would not care to risk damage for either device;

See:

Do not use palm rest or keycap covers on a Mac notebook with a Retina display - Apple Support

Some screen protectors can, when removed, pull up some of the anti-reflective coating on the screen. Same lovely repair cost as above.

No. Do not use palm rest or keycap covers on a Mac notebook with a Retina display - Apple Support