Need Help w/ My Last Few Issues

So the Linux journey has been long and fun, but I've gotta take a break from tinkering for a while for work. I'm down to my last few problem points and would love some assistance:

1. I want to know if there is any way at all to reduce and ideally eliminate the screen flickering that happens when rEFInd initially boots? My screen flashes gray three times before rEFInd shows up and I've tried adding & removing linux from the usegraphicsfor option and mess with resolutions to no avail.
2. Is there anyway I can get an encrypted Garuda system to work with Secure Boot? I've gotten rEFInd and OpenSUSE Tumbleweed to work, but no lock with Garuda despite attempting all of the MOK enrollment and shim copying.
3. Please for the love of god tell me there's a way to Miracast / screen mirror / wireless display! I've tried gnome-network-displays and miraclecast on both distros, X11 & Wayland, native FireTV & Microsoft Display Adapter all to no avail.
4. Finally, I know this is a broken record, but if anybody anywhere has gotten a KVM program like Synergy / Barrier / Input-Leap / rkvm / nikau to work with a Linux Wayland Server and MacOS client, help a brother out.
   Any help is greatly appreciated!