Gear linkage stiff, adjust clutch?

Hello everyone!

I've been having some issues with the circuit for a while now. The gearbox is jerky.
especially in the first three courses. During longer highway drives (over 200 km), it becomes slightly...
Okay, here's the translation:

'better.' Here's the translation:

'But something else I noticed: Even if I forcefully press the clutch pedal...'
The circuit functions perfectly, even down to the carpet fibers.
Normally, I would adjust the clutch cable now, but I haven't.
Unfortunately, it's not (hydraulic). Is it possible to adjust the clutch mechanism in any way?
Should the hydraulic system be bled periodically?
If so, how do I proceed?

My second guess is that it's related to the transmission fluid. This has been running for 6 and a half years now.
It has served its purpose for 190,000 km. Is it really urgently necessary to replace this, or...?
Would that be more like unnecessary and a waste of money? (The level is fine.)

Thank you for any advice in advance.

Best regards, Olli.

Volkswagen Golf 3 TDI 'Joker', 81 kW / 110 hp, AFN engine, manufactured in June 1997.

Changing the oil might help. That's been discussed before. Since the clutch is hydraulic, it adjusts itself, similar to the brakes. When was the last time you changed the brake fluid? If it's been 6.5 years since the last time, you should do it now, as the brake fluid also supplies the hydraulic system for the clutch.

The brake fluid was replaced a year ago. The problem with the clutch is occurring.
It has only been happening more frequently in the last 1-2 months.
If the clutch actuation adjusts itself automatically, this seems...
It's not working properly for me. But why:-?
I could also cut out the carpet under the clutch pedal, but it will...
'Surely there's a more reasonable solution?'
How do I check if the sender/receiver cylinders are sealed?

The release bearing is defective, and the clutch is no longer disengaging properly. Exchange.