You seem confused. If you want a transaction use a transaction. If you don't want a transaction don't use a transaction. If you need a transaction across servic

You seem confused. If you want a transaction use a transaction. If you don't want a transaction don't use a transaction. If you need a transaction across services, that sounds like you've run across a microservice antipattern. Monolith/Microservice changes nothing here - you can have the same issue in a monolith where two different functions are managing transactions and now you want a single transaction. Literally irrelevant.