Immediate off-the-shelf router suggestion needed

Would prefer to buy local and immediately (so BB in all reality); Amazon is an acceptable backup if I have to wait....

gigabit internet connection (apparently my TP-Link C7 can't handle the bandwidth).

any options in the $75-$150 (USD) range that can handle it and run OpenWrt?

Based on your 2nd thread, this would probably work.

But new is probably AX, and there aren't many of those supported by openwrt just yet.

Read the device specific thread

Handle what? Be specific what speed and features you need.

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.