Dug a bit further, that ubuntu bug is just a different, but unrelated breakage caused by openssl updates.
I think yours is the one described in this blog post, which actually covers NixOS: eduroam, OpenSSL 3, and wpa_supplicant - k = 1 cat - Jim Fowler
I’ve looked around for a pure configuration setting, but I think that patch is much easier to do. You’d apparently have to create a separate openssl config file.
Networkmanager should continue to work if you use that patch, too. But I’d definitely suggest asking whoever maintains this network to look at updating their infrastructure in the long run.