I just thought of something I missed in my previous post's.
Doesn't your Z370 take a Intel i9 cpu?
Either way, it's a Gigabyte and probably a higher-end one like my older Z170 Asus ROG mobo.
My...

Removing the r.a.m., s.s.d./h.d.d. mouse, keyboard or monitor cable won't produce a beep. Your p.c. just won't work as all of those need to be installed and plugged in for the motherboard to work....

Most motherboards haven't made a beep sound at pc startup for atleast 4 or 5 year's now.
They only time you'll hear a beep sound is if their's a serious problem, otherwise you hear nothing until...