Why all the BIOS updates? Did you upgrade the chipset driver prior to upgrading from F5 -F31? Then to go to F40 you needed to do: 2. Before update BIOS to F40, you have to install EC FW Update Tool (B19.0517.1 or later version) to avoid 4DIMM DDR incompatibility on 3rd Gen AMD Ryzen™ CPU
Which is where you might have gone wrong and now have this RAM issue. you also needed to do F42g:
- Update AGESA 1.0.0.3 ABBA
- Improve Destiny 2 gaming compatibility
- Correction of PCIe Gen4 being disabled when using a 3rd Gen Ryzen (Matisse) CPU due to AGESA change
That's why the M.2 is missing. From there you can go all the way up to F51 or even F60f but F51 is as high as you need to go. Fortunately, you have dual bios on that board, so you might need to put the 2600 back in to flash back to the beginning and redo this process. X470 AORUS ULTRA GAMING (rev. 1.0) Support | Motherboard - GIGABYTE U.S.A.
You can download the manual there as well, makes it easier to read than a paper one. After you fix the BIOS updating all the way to the F51, you can then try installing the R5 3600 with the RAM and you should be fine but will need to reinstall Windows after putting the 2600 in to fix the chipset driver, since it doesn't update after O.S. install. I don't think you'll need to reinstall the O.S. after the F51 is done to put the R5 3600 in. Lotta work for that board to put a 3000 series in!
"It worked before you broke it!"