I saw some news in the last month that Big Navi is targeting 2x 5700xt performance which is a huge improvement for AMD but that would place the chip at just above 2080 ti but below 3080. Not sure about the validity of the report but it sounds reasonable to achieve 2x the previous high end card...
Based on historical trends, AMD tends to be able to match the 2nd tier from the top Nvidia GPU. I think the new high end AMD will be sitting around $500 with performance slightly higher than 3070 but below 3080.
I've always used ASUS mobos for over 15 years and they've always been solid. It's hard to tell the difference between motherboards from reviews as most will be around 4 stars on newegg, but generally speaking, I've heard better things from Asus