Changer You should'nt have to disconnect hdmi when you hit black screen on boot, usually just switching to another hdmi and switching back to ps4 hdmi is enough. I am in a similar situation and this works 99% of the time.
Currently the 5.4.213 kernel is the best we got for the baikal pro. just don't use "stock" whitehax0r 5.4.213 cuz it doesn't have bt support. if you are on the discord there are some edited 5.4.213 kernels that have bt enabled.
Just about every linux distro made for ps4 is game ready, I think. Most have steam, emulators, etc. installed already but some (like mine) come bare bones. In either case it should be as easy as installing what you want and playing.
