Thank you for your opinion, definitely going to do some more research to find everything for the best price.Be aware the Mortar is an mATX, so smaller format. Won't properly fill an ATX case.
IMO, any of the boards you've mentioned will work great with a 5800X...they all have good VRM configurations with DrMOS power stages suitable for overclocking even 5950X CPU's. Look at features; USB ports (location), M.2 sockets for NVME's, LAN options, etc.
Actually, the B550 E is a little over my budget. I'm sorry for the false info.The Strix B550 E is a the best of the lot. Go for it.
The B550-A and B550-F is the only option.