I found that with GPU rendering, the CPU is rarely all that important to the process, nor is the RAM (for VEAI anyway - which is very handy cause I have a separate AI upscale for the audio tracks that will run the CPU pretty hot)>.
Also Alienware primarily makes laptops and small form factor desktops, don’t they? I’ve had very bad luck with any OEM vendors making those with Windows on them. Some colleagues reported extra thermal throttling for both form factors. When we went head to head against my Surface Book 3, which has an underclocked 10th gen i7 and a GTX 1060 Ti Max-Q, basally the surface book was doing pretty well keeping up with the allegedly full clock CPU and the GPU performance was toasting cards it was never meant to. So be careful.
I think I saw multi-GPU render options, so if you just want to order something primarily for rendering but not a full-size desktop (cause you could stick 4+ maxed out GTXs in there), since you have a Mac already: the M1 Mac mini + 4 Thunderbolt3 eGPUs (one per TB3 lane) might genuinely be better. Worst case you could just run both of your test scenarios in separate instances on separate cards head-to-head to determine The Who’s faster by way of racing them.
EDIT: sorry I’m still a bit loopy - I’m not actually sure the apps work on an M1 - and the M1 only has 2 40Mbit/s Thunderbolt 3 sockets, whereas the 2020 Intel Mac minis have 4 - and assuming the GPU works at all, I doubt that daisy chaining them and cutting their bandwidth in half would be worth the extra GPU cores.