threemcs
my advice would be.... if you want the EOS RA then buy it !
There are several other devices available that are similar to the ASI AIR PRO that DO support the RA. (i wont name them here as i dont want to break any forum advertising rules, if any, but an internet search for ASI AIR alternatives should throw a few up)....
if you already own the ASI AIR then consider buying and flashing a different operating system to a different card and use that, there is some minimal setup involved getting running but the info is out there!
Dont think that ZWO are holding you over a barrell with the EOS RA, they are simply way behind by not supporting it