Cross-instance distributed transactions with Azure SQL Managed Instance

Hi fmantovani, I'm Sasa Popovic, program manager working on Managed Instance distributed transactions. Thank you for the feedback and interest in the feature! If you have more feedback please feel free to post in comments or to contact me via IM/email.
I'd like to address few points from your comment. Managed Instance distributed transactions are in public preview since October 2020. We consider public preview to be a public beta, meaning that anyone with Azure subscription can try the feature and Microsoft Customer Support Services will supply support services. Features in public preview are more likely to have limited functionality (e.g. you can put only two Managed Instances in Server trust group) than to be buggy, and I can tell that at this point we don't have any known outstanding bugs related to Managed Instance distributed transactions.