Hard shifting like clutch is not disengaging?

Hello,

There could be a few different reasons for this issue.
First of all, make sure that the fluid is at the correct level and that there are no leaks. As low fluid of leaking components will not allow the system to generate enough pressure to operate properly.

If the fluid is full and no leak is detected, it could be a failing master or slave cylinder.
Over time the internal seals of these components go bad and start to leak internally. This causes a drop in hydraulic pressure and results in similar issues that you are experiencing. Typically, there is no external leak that can be detected.

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.

https://www.2carpros.com/articles/throw-out-bearing-replacement