No. Generally, newer GPU's are fine on older MB's.
But in this very specific situation, maybe. The reason is the m.2 slot on this video card. It requires the slot for the GPU to share bandwidth correctly with the GPU and other m.2 slots on the MB. So, ASUS is not guaranteeing it will work...
Best Buy? I've picked up several Open Box, Excellent Condition from them. Some are available for shipping. Saw a 4070 Super for ~$500 a couple weeks ago. I see several Asus dual fan versions in stock.
I run a 4090 and an LP 4060 from MSI and Gigabyte daily. Both are fine. The other 40's I have are all Gigabyte basic open box models I picked up on sale. No issues with any of them.
You came to late to the party. The 1080ti was the last SLI setup I put together. Had been doing SLI systems for years. I dumped the second GPU and have been single card since.
For family pics, especially those who are not living, start using Ancestry. Don't need a subscription to contribute. You are the product, there too. Digitize and get rid of, yet save, the old stuff for the next several generations.
Look at a NAS device and something designed for backup use...
[ION] for holding the anchor spot on PG CUL during the Pentathlon. We'd be farther down the stack if not for their contribution. Also, for sharing some tweaks that helped optimize others'.