Backwards compatibility

Hi there, I'm looking to upgrade my current server to an E7-8850 v2 and need a new motherboard for it. I looked on CPU World and it lists the socket as LGA2011-1. I've tried around for a motherboard, but I can't find any LGA2011-1, only LGA2011-3. Is it ok to buy a v3 motherboard and use this CPU?

Silly question. I am about to update to a 12th gen. system, and I already have a RTX2070 with PCIe 3.0. Motherboard would be a Z690 ROG Strix -f. Is PCIe 5.0 backwards compatible with 3.0? Will the motherboard adjust bus speeds automatically? Thanks in advance.

Just reciently bought the Ryzen 2400g. Also bought some G.Skill Ripjaw V 3200mhz RAM. In the bios it says its running at 2133mhz, it gives me the option to go up to 3200mhz but it crashes. I did not play with the voltage cause i'm not very informed on that stuff. I would think it would preset to...