I think to start your wife should speak to HR or their direct Mgr and ask for 3 hrs to attend the virtual ceremony, what kinda of company do you work for that will not grant it? does she have an ERC or CG at work for example my company has a CG = Community group called #immigrants. and we get time off to do this virtually but if its in person we will allow them to use a vacation day, or take a future paid stat day off and still pay 2.5x pay on that day.
But it is per the company and their policies, In Alberta, Canada, there are no specific laws that guarantee time off work without penalty for citizenship ceremonies. However, in Canada, federal law grants employees certain rights and protections related to time off work for specific purposes, such as voting in federal elections. While citizenship ceremonies are not explicitly mentioned in federal legislation, some employers may have policies or agreements in place that allow employees to attend such ceremonies without penalty.
Good luck to her, I would suggest making sure she is online and ready for her ceremony or just taking the day off n be done with it since her company sounds horrible and have no regard for work-life balance. ( but just my 2cent)