I just got my first ever pre-built system - I was waiting for the 3950x to drop, but I got a crazy good deal on a 3900x from Cyber Power:
3900x
16Gig 3200mhz memory
5700xt
1TB NVME SSD
800W Gold PS
All for $2000 CAD - I couldn't build a system cheaper going the DIY method. Once you factor in the Windows license and misc addons (keyboard, mouse etc.) I saved $400. While I am normally against pre buids, Cyberpower uses all brand name components: Asus x570 motherboard, Inwin Case etc.
I added another 32G of ram, 2TB SSD and swapped my 2080 for the 5700xt.
I now have:
3900x system @4.25ghz all core
Delidded 7820x @5ghz
4960x @ 4.6ghz
4770k @4.4ghz
x5660 @stock (I used to be able to get 4.6ghz out of it, but I think the motherboard is dying)
8750h laptop
6700HQ laptop
5700HQ laptop
Surface 4 pro
Random assortment of tablets
Realistically, I only use two of these computers, but something about having my office jammed full of hardware makes me happy. It's what the nerdy teenage me dreamed of, and I finally have the money to do it.