Hi @Alan Niedelman ,
stop and start an Azure SQL Managed Instance is still in preview: Stop and start an instance (preview) - Azure SQL Managed Instance
As far as I know there is no option to force a restart of an Azure SQL Managed Instance. But you could create a support ticket with Azure support to get your issue solved.
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten