I have msi edge wifi ddr5. I’m happy with it.

Non-main pcie slots do occupy the lanes from chipset instead of cpu. This means the ssd in the main slot should maintain its performance, and others should be slower.

Here it is

https://msi.com/Motherboard/MPG-Z790-EDGE-WIFI/Specification

I would go for intel day and night. Better card. Better technology. Better support.

Here’s an article about it. https://www.tomshardware.com/news/stable-diffusion-for-intel-optimizations

3060 would cause fewer headaches. A770 would be better once you get things working. Btw, a770 has somewhat mature support for ai workload, too.