Linksys EA8300, quad core, tri-band, 256/256MB, handles around 400Mbps w/o software/hardware offloading enabled. Enabled should handle around 700-800Mbps - but no SQM. SQM takes it back down to 250Mbps.
Used $50USD (+shipping) on ebay. I bought 3 to make a mesh. Works great!
Used/renewed on Amazon $80-120USD.
Dual firmware (easy to use/hard to brick), loads 19.07.7 easily from the linksys management screen. After flashing you will have to ssh into it though as LuCI is not included in the EA8300 generic factory bin.
The EA8300 lists for $180USD new at bestbuy.
Recently tested mesh inter-connectivity at 359Mbps (many thanks @cgomesu).
It has 2 x 5Ghz radios, so it can probably do 2 x 359Mbps = 718Mbps (not tested yet) plus 2.4Ghz ~100Mbps.
Not too shabby. It's not the fastest but its damn good for $50USD (I paid $100CAD each). Dual 5Ghz + 2.4Ghz. 2.4Ghz coverage is not as good as it uses internal antennas but not bad - especially for $50.
The C7 v2 tends to limit 2.4Ghz txpower at -25 dBm (316mW) versus the EA8300 full txpower -30 dBm (1000mW).
https://openwrt.org/toh/start
TOH is your friend.
https://forum.openwrt.org/t/so-you-have-500mbps-1gbps-fiber-and-need-a-router-read-this-first/90305
At the time of writing 1GB routers in the $80-120USD price range are typically ethernet only. And even then might only do 500Mbps up and 500Mbps down simultaneously (1Gbps total throughput).
https://openwrt.org/faq/which_router_should_i_buy
https://openwrt.org/toh/views/toh_available_16128
https://forum.openwrt.org/t/best-router-for-gigabit-wan/54170
https://www.technadu.com/best-openwrt-routers/228185/
### x86_64/AMD64
For those desiring “true” gigabit throughput or high-speed VPN, a low-power x86_64/AMD64 SBC (single-board computer) or an ITX board ([Information Technology eXtended](https://en.wikipedia.org/wiki/Mini-ITX), a small motherboard form-factor) with AES-NI (Intel's [Advanced Encryption Standard New Instructions](https://en.wikipedia.org/wiki/AES_instruction_set#x86_architecture_processors)) and dual NICs is an option. With proper component selection, such devices can actually consume *less* power than a high-end, all-in-one router, even when paired with a suitable AP for wireless.
https://openwrt.org/toh/recommended_routers
https://bcca.org/best-openwrt-routers/
R7800 might have problems loading OpenWrt sometimes.
https://openwrt.org/toh/netgear/r7800
https://community.netgear.com/t5/Nighthawk-WiFi-Routers/NightHawk-x4s-R7800-WAN-to-LAN-Throughput/td-p/1741404
https://www.reddit.com/r/openwrt/comments/hvonpj/sqm_on_netgear_r7800/
You could get something like the EA8300 to tide you over until you can get something faster and then repurpose it as an AP or extender.