Yes, I see that okular (21.04.3) won't open it. Actually, okular does
say "This document has XFA forms, which are currently unsupported.
It's also odd that the message which is displayed implies that Acrobat
Reader is available for Linux, even though it's not available.
How is Ghostscript involved on Windows?
Is there any hope of complaining to the Alberta government that there
is no access to the form without being forced to use proprietary
software? (Probably not, but it's a thought.)
Finally, if you search for "acrobat xfa forms linux" you will find some
suggestions.