I have a guide I’m maintaining, you may find something in there useful My Journey to a reliable and enjoyable locally hosted voice assistant
Regarding the FutureProofHome Sat1, I’ve been following in their discord and an outside contributor has a proof of concept for using all 4 mics and it has considerable improvements to SNR. I believe they’re doing more testing but that should hopefully improve things 
I’ve tested quite a few different GPUs and devices, mainly with a mini PC and an eGPU. Right now I’m using an AMD 7900XTX via Vulkan and it works fairly well. It’s surprising to me how much effort AMD seems to be putting into ROCm and yet how disappointing it is.