The Community Commons module in the Marketplace has EndTransaction and StartTransaction actions. You can use these to make the transaction end earlier and commit to the database, and to also start a fresh transaction in a microflow.
https://docs.mendix.com/appstore/modules/community-commons-function-library/#orm
Another approach could be to break up your microflow into smaller tasks that run in a task queue. Each task will be in its own transaction when run.
https://docs.mendix.com/refguide/task-queue/
I hope this helps. Good luck!