I have a 2019 MacBook Pro 16" i9 with 16 Gb and BenQ 32" 4K monitor. I am using a USB-C cable to connect this monitor.
At starting it was working fine but after a few months (during those days macOS was updated from time to time), it became impossible to use both screens. The kernel task is getting 1000+ and the MacBook is getting hung, I can not even move the mouse cursor properly. Then I have to shut down my MacBook via the power button.
Then, after I try to use the external monitor directly (the laptop lid will be closed) but still some times kernel task gets 1000+ and I can not work, then I have to restart MacBook again and again.
I am not using any heavy software, just a browser, Visual Studio Code, and PHP/MySQL/Apache.
It feels like I am using a 15-year-old machine.
I cleared the cache, rested the SMC, and reinstalled the OS. I'm tired of using the charging cable and monitor cable on different sides but still, I am getting this issue. I contacted support but still no solution.
Submitted a bug report to Apple but no response.
I bought an external monitor so I can work on 2 screens but I cannot, I have to use a MacBook screen or external monitor only. can not use both at a time and even when I am using an external monitor only then still many times have kernel task high issues and MacBook got too slow and it's impossible to work and have to restart the machine.
Sometimes, it also overheats when the kernel task is high (after the kernel task is high not before).
How can I fix this issue so I can use both screens?