Deutschlandticket with CC or Cash?

With a credit card using the MVV app. You cannot buy with cash because it is a monthly subscription, however you can cancel it so you do not get charged for a second month.
https://www.mvv-muenchen.de/en/tickets-and-fares/online-und-handyticket/frequently-asked-questions-mvv-mobileticket/index.html

I second credit card but recommend BVG (Berlin public transport) for buying the Deutschlandticket because everything easy online in English:

Purchase: https://www.bvg.de/en/subscriptions-and-tickets/subscriptions/deutschland-ticket

Cancellation: https://www.bvg.de/en/subscriptions-and-tickets/subscriptions/subscription-cancellation

FAQ: https://www.bvg.de/en/deutschland-ticket/faq

Thank you!
Can I still buy it for May?
I only see the June buying option.
Mary