X470 Taichi Ultimate vs X570 Taichi

There should be no problem using PCI-e 3.0 M.2 in the PCI-e 4.0 M.2 slots.
They just will run with PCI-e 3.0 speed.
You also can put a PCI-e 2.0 or a PCI-e 3.0 GPU in the a PCI-e 4.0 x16 slot. The device defines the PCIe speed.

brucer wrote: I would get the x570 Taichi.. one reason being priority bios updates for the x570 Taichi.. you'll also have pcie4 for future upgrades such as gen4 drives, they are too expensive now but give them 6 months and it might make for a awesome upgrade..

I did follow brucer's advice, and reluctantly passed on the x470 Ultimate, mostly due to the lack of the Bios Flashback feature. I had read somewhere that at some point a guy was updating the Bios and the power went out, and rendered the board inoperable, so I'm hoping the Bios Flashback feature prevents that. I thought some boards even had a backup Bios chip, but I'm not sure which ones. I also decided that PCIe 4.0 would end up being a benefit if I get a PCIe 4.0 NVME.

So, instead of the X570 Taichi I picked the X570 Gaming X. I don't really know if it was worth it, maybe somebody with greater knowledge could comment, but I thought the Gaming X with the WiFi6 might help at some point in the future. Also the LAN for the Gaming X was at 2.5 Gb vs. 1.0 Gb for the Taichi. I'm still not sure if the VRM for both are the same or if one is better than the other.

Maybe somebody could answer the newbie questions I have about the X570 motherboard.

With the help of experts here, I'm understanding the PCIe slot bandwidth situation, x16 vs. x8 vs. x4 vs. x1.

I still am unsure about the three Hyper M.2 slots. I guess M.2_3 shares the PCIe lanes with PCIe_5, as it is an either/or usage. So are the other Hyper M.2 slots then additional PCIe 4.0 lanes that bypass the "regular" PCIe slots? Is it then better to use M.2_1 or M.2_2 instead of M.2_3, does it impact the speed of the M.2 NVME ssd?

It also seems that if you use the M.2 slots, the heatsink that comes with the M.2 NVME ssd can't be used, so is it better, or can it be done, to put the M.2 NVME ssd in the PCIe_5 slot? Would the drive operate slower in the PCIe_5 slot? Does the heatsink from the motherboard keep the M.2 drive cool enough?

Now the obvious newbie questions:
1) How does an M.2 SATA drive work in the slot? Is there a SATA cable that is somehow attached?
2) On the ASRock site, https://www.asrock.com/mb/AMD/X570%20Phantom%20Gaming%20X/#Overview
it shows "Unbeatable Heatsink Armor" picture, which has one labeled "M.2" and the second labeled "HYPER M.2 SSD" so is there a difference between the "ordinary" M.2 and the "HYPER M.2?"
3) Can you do a RAID-0 with the M.2 drives, and if so can it then be bootable?

Thanks for all the help.