I agree, first check the “slop” in the cable when the cluch is not engaged. If there’s a lot, then tighten it up and see if that fixes things. There should be a little “slop” but not excessive.
If that’s not the case then…
When the engine is running and everything is warmed up, in gear, and pull the clutch can you apply the break and does the engine keep running? If so, all is fine, if not, you have a problem.
If the engine is cold and you pull the clutch, it might not seem like it’s disengaging… With the transmission fluid and the number of disk/pressure plates, it might not feel like it’s working, so it’s best to try as I mentioned above.