Looking for a cheap Wi-Fi 6 router to use with Xfinity XB7

Hi

I’m planning to put my xB7 router in bridge mode and use another router for the rest of the home network.

The main reason is that I want more control over DNS. I’m planning to run AdGuard Home/Pi-hole on a Raspberry Pi and eventually set up a small NAS-home cloud.

Im looking for a router, preferably something cheap that I can buy used?I No need Wi-Fi 7, and not looking for a gaming router.

What models should I keep an eye out for on eBay/Facebook Marketplace/etc.?

I was looking at things like the TP-Link Archer AX21/AX20, but I’d like to hear what you guys actually recommend.

Thanks!