Dell XPS back in the day used to actually mean something, I had an XPS 8300 (since it was dirt cheap, and cheaper than building). Well I went to upgrade the video card and it would reboot all the freaking time(power supply)
It was a uber pain to fix a CX corsair 650 into that case and the air flow was a nightmare having the 3.5 drive bays maxed out. Thing was like a furnace on the inside.
Dell even on the XPS has crap power supplies and cases are trash.
Dell customer service years ago was subbed out. I had a bad DVD drive on a new Dell 4700. They finally came out and replaced it, but it was an uber pain, and wouldn't just ship the part. (yet again I got the 4700 based on cost, instead of building)
I would try a local computer store?? Not a big thing on the internet, somebody you can see face to face and deal with. If you have a friend or a Microcenter close use one of them instead.
If your not going to game, and your just going to use chrome/edge, prebuilt Dells are fine. If you something better its really fun to pick out a good PS and the parts. Even if you don't go super high end, good chance you can reuse the case and PS for the next build and save money!!