I have Kubuntu 18.04 installed on my machine and sometimes it gets frozen randomly and when this happens the only thing I can do is a forced shut down. I have experienced this in Kubuntu 20.04 and in Ubuntu 20.04 too even more frequently.
The only Ubuntu version in which I haven't had this problem is in Ubuntu 18.04. I think this is a problem related with the kernel version but I'm not sure.
These are my pc specs, I have an Intel integrated graphic card:
This is the partition table: