6GHz has worse penetration, but I have no experience with WiFi 6E. It's probably still faster than WiFi 5 or 6, though since you are just going through a floor? The bigger issue is the latency, and I think only WiFi 7 has improved on that.
Might be worth getting a quote from an electrician to run some CAT6 cable in the walls? Fiber Internet has multi-gig speeds now and its only going to keep advancing, so it may make more sense to invest now in cabling if you don't want to rely on WiFi forever. Plus WiFi 6E stuff is pretty expensive, I guess WiFi 7 hardware should be compatible now too but it's just as costly.