It is easy: right-click the app icon and choose to remove it.
I do not reproduce your problems. As for how much it uses the GPU, read the FAQ on the web site. It is not a heavy GPU using app unless you opt into it in the Settings menu. You probably have something installed on your cluttered system that is interfering with Shotcut and would need to reinstall Windows.
When the log says “<Util::isMemoryLow> available RAM = 30591952 KB” it is not telling you that memory is low. This is the low memory checker reporting the free memory.
I am not able to make Shotcut work good on every system because I do not have every system. Neither do I have the time, patience, and mental health to try to troubleshoot it on every problematic system. There is nothing I am personally going to do about this. There is a very small chance that some other person wil but I doubt it. So, here’s the deal: since it is freely available, either it works for you on your system: you decide.