Check if HP Support Assistant is running or not. Also, check W10 Task Manager when it crashes next time to see if there is a process which runs and uses a huge amount of CPU percentage. Lately I noticed that the fan of my otherwise very quiet HP Elite Desk is occasionally running at high rpm. After some investigations, I found an exe file running and taking something like 50-70% of my CPU capacity for no understandable reason. I did some googling and it said that it's a buggy HP app or driver, but there is no fix or recognition on HP, except that the task can be killed and then everything is back to normal after that. I don't remember the file name, but in case it happens later on today, I'll add the information here. Anyway, it seems that my computer works fine without that task, so for now, I just kill it when I hear the fan speeding up. No side effects noted yet.

I don't know if the above would help you, but I suspect the issue is not UCCNC, but your installation, or Windows trying to access the server to get updates. Another question is your Windows version. UCCNC is not very demanding on the computer performance, so your PC is not too weak. After all, it can happily run on a 20+ years old PC with W95 or XP also, so if changing to your brand new Dell would help, it is probably because the differences in the installation, not because of the better PC.

What I would do is that I'd just do a clean install of the HP, not just UCCNC, but start from factory reset with the original installation. After the PC is up and running with Windows, install ALL updates (HP and Microsoft) and don't kill any tasks (you may have killed one too many earlier). Once that is done, install UCCNC. That way you get a fresh start. I am running Windows 10 Pro on my computers, so I can prevent or postpone W10 updates, but I really don't believe that Windows updates causes your issues. It won't crash UCCNC unless something else is wrong.

Note, that I am assuming you are running UCCNC version 1.2111, which is the latest official release. Test versions can have all different bugs.