it says on the box Ryzen 4000 and 5000 ready now Ryzen 7 5800x falls into that category or should I try a BIOS flash before I do a RMA this mobo has a BIOS chip that is soldered to the board and just can't order a new one
"ready" is a bit misleading with AMD chipsets in some situations as it can simply mean there is a released BIOS which offers support.
I am not aware that motherboard manufacturers have offered the BIOS chip as a user installable part in quite some time. You might be able to contact the manufacturer to see if they will or can offer guidance on having it done. If you know any PC enthusiasts they could have a CPU lying around that would work. Of course, my answers are specifically in relation to a BIOS update being your issue as it was presented that way.
Do you have any privately owned PC shops anywhere nearby?
Perhaps look on your used sites to see if you can find a 2xxx or 3xxx super cheap to use to try it? ( I would suggest 2xxx as 4xx series chipset was released "for" them)
IMO, this long lasting "support" for the AM4 socket came back to bite a lot of end users in the fanny, getting EXACTLY what you are dealing with right now. Don't get me wrong, love what Ryzen did for the market and competition but this was a clown show for folks looking to scoop new old stock or used equipment without knowing better how to deal with it.