Thanks for posting. Apologies that your system is not performing as expected.
If you still require assistance and the system is under warranty, you may contact me privately. Be sure to include your personal information (name, address, telephone, email) and your computer's service tag number in your message. Thanks.
If there is no warranty, then you could contact our Out of Warranty team to get a quote for a paid service request.
I have the same problem with my laptop Dell XPS 13 9380. I tried to fix it as your solution but it's quite in few minutes only.
How can I fix it or I will use Dell XPS 13 9380 to dry my hair?
For some reason, the fan stops completely when I open the task manager to see what's running. It's as if it gets scared or something (like the double-slit experiment in Physics!) 👨🎓
I do this once every time I restart the PC and I'm Ok for now...