We announced at Ignite that we are actively working on bringing dynamic plus aliases to Office 365.
To get around existing usage, the plan is for an opt-in setting. Our ETA is to have this available for all customers by the third quarter of 2020.
I will keep you updated in Uservoice on our progress.Anonymous commented
I would suggest any domain that has a + will have the feature disabled and require an admin to go enable it and reconcile any emails or aliases that exist with the + present.