Which home routers can resolve recursively instead of needing upstream DNS? I’ve never seen this across many brands of home routers.

Your ISP publishes T&Cs and a privacy policy too.

Furthermore, your ISP’s resolver is probably in your ISP’s network, so your queries don’t have to go out through peering/transit.

"Which home routers ..."

Drayteks have a lot of options built in, including a funky DNS implementation. I've personally largely dumped them for rather more complicated jobbies but they are still very capable.