Standoffs are not part of the AORUS X470 Ultra Gaming product. They normally are included with the PC case. Some cases have standoffs stamp into the steel. You may want to check the case instructions.
The holes to put screws in are suspended above the backplate. Are they built in standoffs? If so, why did this case come with a non-built on standoff...
I have built a system with that case before. Doesn't it provide labels to where the standoffs go. You have an ATX motherboard. Make sure there is a standoff in all places labeled 'A'. I apologize if I am thinking about the wrong case.
They do suspend the motherboard from the back plate, if that's what you're talking about. (Sorry for my lack of knowledge btw, this is actually my first build).
That case has built-in standoffs. However, one standoff needs to placed manually because its location depends on the motherboard's form factor. I believe the spot is marked with 'A' for ATX boards.
As long as every motherboard's hole can be screwed in, then you are good to go. If one of them cannot, then that is probably where the lone standoff should go.