Is it good not to use your MacBook Pro like more than 2 months and keep it powered off

See the long-term storage info here: Batteries - Maximizing Performance - Apple

If you’ve previously stored the Mac and are now resuming use and are having issues, what might those issues be?

Make sure that it is charged to at least 50% before you stop using it.

Shouldn’t be a problem. Some try to discharge to the middle of the charge range for any storage, but that’s not strictly needed.