I’ve had pretty good luck with building machines. I built 2 desktops about 5 years ago (4790K processor); they run Boinc projects full time (at least when I’m not using them). https://pcpartpicker.com was helpful for reviews, looking at builds and components, and price comparisons. It can take quite a bit of time to look at what others have built, and sort thru options for cases, cooling, power supplies, memory, and the like. I’ve always bought known brands from reputable retailers (mostly Newegg).
I do love Linux (Debian derivatives) for stability, security, and maintenance. Mint works great on my desktops and older Dell laptops alike. A daily cron reboot is helpful for systems that run continuously.
I looked at Puget Systems too, and liked their products. I also liked System76, but I’m not sure about the reliability aspects. In the end, I opted to build rather than buy; I’d definitely build again in the future.