Sort of. The beta firmware Fraser shared (0.53) would allow me to get all consoles on open with 'NAT Filtering' set to open, but before long one or more of them would end up as strict / not connect to COD servers at all and the only fix I could find was to reboot the router and/or the consoles, which I got tired of - I reset this router more in the first month of owning it than I have every other router I've ever owned. I still run 0.53 because it seems to manage much better pings on Connection Benchmark (down from 20 something to <10), but now have Nat Filtering set to secured (which usually means at best 1 console might get open, but I never get strict), and I'm pretty sure things like QoS, traffic prioritisation and geo-filtering don't work properly in 0.53 (or at least not as well as they did with 0.52).
As you've said, it's very frustrating an older router like the R7000 did it all right out of the box. I check back here every now and then to see if there's a proper firmware update that might fix it, but am also keeping an eye out for a WiFi 6 option with similar features as I'd pretty gladly dump the XR1000 if something else came along (by no means a reflection of the support you get from the Netduma guys on this forum, which I think is great).
Would love to hear if anyone else has managed to fix it and had it stick for more than a day or so.
P4UL