@EdwardL
We had exactly the same problems with A7 IV and we had to wait for 6 months. Maybe you will be luckier. I found I had two alternatives:
either use Sonys Imaging Edge which not is so bad at all. It´s free for you and will give you a chance right away to test your A7r V ARW
or you can download the Hexeditor HxD and the Macroeditor “MacroEditor” (Windows)
If you use Mac I´m sure there are some applications you can use there too. Below is a link that explains how to exchange camera version codes in your files. Try to use the model code used for the previous version of your camera or you can actually use even the codes for A7 IV. It will also “let you in”.
If you want to automate the exchange of the codes download the macro editor “MacroEditor”. A working macroscript is embedded in the link below.