X670 Pro RS BIOS won't update to 4.10

I am guessing you mean the X670E Pro RS?

That is very odd, are you following the same steps with 4.10 as with the other
versions?
Did you rename the extracted ROM file to creative.rom ?

Obviously you will need to follow the usual steps to use flashback:

Use BIOS Flashback: If you cannot get into the BIOS to use Instant Flash, use the dedicated BIOS Flashback button on the rear I/O panel. Ensure the BIOS file is renamed to creative.rom and placed on a FAT32 USB stick. Clear CMOS: Clear the CMOS by turning off the PC, removing the power cable, and either using the onboard "Clear CMOS" button or removing the coin-cell battery for 5??0 minutes. This resolves many update failure issues. Check USB Format: The USB drive must be formatted as FAT32, not NTFS or exFAT. Use a USB 2.0 drive if possible for better compatibility. Re-download/Verify File: The file on the website may have been corrupted or improperly packaged. Verify it is for the "X670E Pro RS" and not a similar model.

I hope this helps.