Clutch pedal gives way at hot temperatures

Hey, with my Mazda mx-5 NC 2.0 L Niseko, the clutch pedal is always after this year when it gets hot, so it goes through empty until I can’t get in/out of gear at all. After a certain time without any action, the clutch goes again so that you can at least couple and the next day it’s normal again. I noticed this last time when I was standing in the traffic jam and could hardly drive on. Once you are in, it goes without coupling somewhat, abe r is a problem. The lower clutch cylinder has already been replaced..and since I have a grinding noise, if the clutch pedal is not kicked, which disappears as soon as I step in the clutch, I also read the back bearing (Bzw then the whole clutch, since already removed). The problem with the grinding noise still exists when the car is cold and today where it is again very hot, I realize that the other problem still exists. Before I try to share any more good luck, I wanted to ask you for advice, if any of you had the same problem? Greetings