Ok, this is coming from an inside source at Micro Center.
"Monday Tuesday, Thursday and Saturday before noonish for 3090 cards."
Go in person, line up early and lock down the card. They are overstocked currently (depends on location obv.)
Restocks for NVidia's new 30 series cards are now happening weekly and here is how to get them.
3070 and 3080 cards are a toss up right now, so check daily if you really want one. Show up early and hope for the best. At least we have some insight on 3090 cards and your best chances on scoring one.