There are two choices, the way I see it:
1. Invest in a decent router (probably $150-200 at least) and throw openwrt on it. You'll need something with serious CPU beef because openwrt relies more on software than hardware, and most routers use hardware for QoS etc., hence the price tag. You'll also need to actually understand the multitude of settings offered by openwrt if you care at all about security or performance -- this is nontrivial if you aren't already a network engineer.
2. Buy a used Apple Airport router. The last generation support AC wifi, which is... basically as fast as the best things out there right now, barring wifi 6E. On the plus side: this comes with mostly sane defaults and good performance, I easily get 600+ mbps up/down on my gigabit internet. On the downside... I think you can only configure airport routers through macOS (and a mostly-dead iOS app), and they don't let you configure all the settings you might want. A fair tradeoff for good, non-footgun defaults IMO, but YMMV.
There's also the third option of creating some bespoke raspberry pi + wifi hardware solution for yourself, but that's likely to get you punched by your flatmates when it inevitably reboots incorrectly during a power outage or overheats or whatever and suddenly you need to spend 2 hours debugging problems without a working wireless connection and everyone else is pissed they can't use the internet. Unless, of course, you're a brilliant network engineer who would never make a silly mistake or have a bug in their custom router solution.
Which I guess is why most people use Google or Amazon spyware for internet in their homes.