There is no consumer grade router that can rout at 8Gbps (not even with IPv6 which uses less CPU), so your best bet is using a PC full of 10GbE ports as a wired-only router, and adding all the access points (also each with at least one 10GbE port) you need for the wifi. It's easy as pie to configure VLAN tagging on any routing software intended for PCs.
Any 3x3 Wifi 7 or 8 device should be able to do justice to 8Gbps under ideal conditions (as in no interference, less than 10' away), but despite all the marketing speak, latency on Wifi just hasn't been a priority because it just doesn't produce gaudy numbers for the marketers to put on the box. The lowest latency Wifi is still from ath9k which was open enough to be used to develop the
Make-Wifi-Fast project and that's only Wifi 4. None of the chipset makers open-sourced their drivers for Wifi 5 or newer, to prevent competitors from seeing how they do things.
Mesh doubles the latency because there are now two Wifi links in series instead of one if you use the 2nd radio as a wireless backhaul. If you wire them up as wired APs instead, then all that extra cost was just so you could manage all of the APs at once using the same interface. That may be useful for an organization managing hundreds of APs but is hardly needed if you only have two or three.
Extenders are always the last resort because not only do you get double the latency, you also get half the bandwidth because unlike with Mesh they receive and transmit using the same radio.