Thanks for the observations and the recommendation! I'm just speculating, but since the dedicated backhaul has been a staple of the top-of-the-line Netgear Orbi systems from the beginning, I imagine they will be one of the first tri-band mesh systems utilizing the 6 Ghz band for that purpose.What you're seeing is likely the combination of enough people blindly throwing money at a problem (poor Wi-Fi) with supply-line disruption due to Covid-19.
If what you have works well enough, leave it alone. The timeline for new 6E routers will be Q4 this year. Those will likely be top-of-line tri-band models and will be priced accordingly. Unlike current tri-band, which splits the 5 GHz band into two groups of 4 channels (in the U.S.), tri-band 6E will have 2.4, 5 and 6 GHz radios. If you really want best performance for 6E devices when they appear, you'll want tri-band.
Tri-band mesh systems using 6 GHz for backhaul will also appear, but not sure when.