Here in our company, we have the 99$ standard plan of shinyapps.io, which has been really useful to us. However, a new IT requeriment is that logins need to be based on the Azure Active Directory from the company.
I haven't used shinyapps.io, but I don't see any reason why it shouldn't work. If you run into problems, you can post another question here or open an issue at the AzureAuth repo.