https://bugs.winehq.org/show_bug.cgi?id=47167
zurohki@gmail.com changed:
What |Removed |Added ---------------------------------------------------------------------------- CC| |zurohki@gmail.com
--- Comment #9 from zurohki@gmail.com --- The Battle.net client doesn't work properly with Wine built with GCC 9.1. Never occurred to me it might be the compiler until googling the "004c:fixme:bcrypt:BCryptOpenAlgorithmProvider algorithm L"\8001" not supported" line I was seeing led me here.
Someone pointed out https://source.winehq.org/patches/data/166316 to me, which fixes the issue for me.