Those RAM sticks are solid, but RDIMM can be tricky with X570 boards. Check if your BIOS is updated; that might help. For a budget build, consider something like the ASRock Rack X570D4U, which supports RDIMM.

It sounds like you’ve got some nice RAM there, but I get how frustrating it can be when it doesn’t boot up. For your setup, I’d recommend checking out workstation motherboards from Supermicro or the ASUS Pro WS series that specifically list RDIMM and ECC support. When I built my workstation for 3D modeling and rendering, I went with a Ryzen Threadripper, and it made a huge difference in performance. With your budget of $3-3.5k, you can definitely grab a solid CPU, a good GPU for rendering, and enough storage to handle your projects.