It sounds like an issue with the clutch master/slave cylinder.
Here are a couple of guides that will help with explaining this issue and how to replace the slave:
Basically the slave leaks and it doesn't allow the clutch to fully disengage the flywheel which makes it hard to get into gear when the engine is on.
See attached for replacement procedures on those items.
Let me know if you have any questions.
Images (Click to enlarge)
Tuesday, July 6th, 2021 AT 11:38 AM