Yes, this motherboard supports PCIe Gen 5. Specifically, the PCIe slot that connects directly to the CPU supports up to PCIe 5.0 x16.

2x Adressable V2 RGB LED Connector (JARGB_V2) 2x RGB LED Connector (JRGB)

Yes, the X670E versions provide more lanes. This means that you have more options for connecting SSDs, graphics cards, etc. without having to accept a significant loss of speed. B650 is a slimmed-down and cost-effective chipset that is recommended if your requirements are lower.

The two products are identical and differ only in their source of supply. This is the reason for the differences in price and availability.

hello, no, there's no adapter for that, it would cause too many malfunctions, but it's all good with your future new 1200w power supply, it's even a lot for this configuration, a pure 1000w power supply would be sufficient, I hope I've helped you.