No they are for the bed plate leveling screws. There are no springs in the system to keep the bed from falling. You can try using (POM anti-backlash nuts from Amazon)[https://www.amazon.com/gp/product/B07XYR3F4C/], but they're not guaranteed to make it any better, they're really designed to help with taking up backlash, not keeping the bed up.

Its fine when its all powered, only happens with power off, this should not have anything to do with voltage at this point. I did notice that after I press on each side z screw spins a bit lowering that side. I think its because the new backlash guides have much less friction than brass so screw doesn't have the same stability. I bought these https://www.amazon.com/dp/B07XYR3F4C?ref=ppx_yo2ov_dt_b_product_details&th=1 not realizing they are not metal. So I may replace for brass version since these might be too slippery good :)