I have a Dell XPS 13 9360, though I am running ubuntu 18.04 on it. I remember there being a patch to the mainline kernel which addressed many of the wireless problems. I'm not sure if those changes ever made it into the CentOS kernels. Some of the Dell XPS 13's had removable ethernet interfaces while most of the more recent ones had the killer interfaces on the motherboard. I'm not sure about the 15 inch models. Mine had a removable interface and I replaced the killer card with an intel card and that helped quite a bit. Regarding the CPU throttleing issue, there are a bunch of posts out there that claimed that the thermal pasted was not well applied to the CPU heatsink and some people had success with carefully removing the heatsink and applying a good quality thermal paste and then reinstalling the heat sink. Would be much better if Dell support would address these issues properly, but the response from Dell on these issues have been very hit or miss. Some people have had them fixed by Dell and others, including myself never reached a customer support person willing to address them. Nataraj