I travel for work and looking for the most budget friendly and compact mini p.c. to play d4. This is about all the p.c. will be used for so u have no need in spending any more for anything extra. Thanks

MSI has 14" laptops Starting $399.99. That would be your Entry level gaming + medium workload performance.
May want to spend the extra 100$ for a 15.6" that has a number pad on right side vs buying an external number pad separately. ( if you need a number pad that is. )

You could get a decent tablet or something with mouse/keyboard, and use cloud gaming services.