I don't think it would cover it in RAW. Your fastest UHS-II cards top out at 300 MB/s theoretical maximum.
R6II RAWs are 30 MB per file, and 40 fps gets you to 1200 MB/s, so you'll hit buffer limits. TDP says buffer depth is about 110 on the R6II or 2.5 seconds or so, which isn't a lot especially if you take the potential new pre-shooting features into account.
With CFE Type B 2.0 cards, you get a theoretical maximum of 1400 MB/s and you'll have a lot more room to work with.
The other advantage, as some other posters have mentioned, is that CFEB cards are faster and cheaper than SD cards. A SanDisk 512GB Extreme PRO UHS-II SD card is $600 on B&H right now, while a SanDisk 512GB Extreme PRO CFexpress Card Type B is on sale for $160. 1/4th the price for 4x the performance.