Use iperf3 if you can.

You could also just use dig, ping, and traceroute to check the path.

my router should know it’s own IP and not bother sending things out into the world just for them to come back

This is correct: https://en.wikipedia.org/wiki/Network_address_translation#NAT_hairpinning

If it’s not working, check the configuration on your router. (Your ISP should also be doing this at their edge, but maybe not.)

Also, you should really not be exposing services to the Internet that you don’t have to. Put it all behind a VPN.

You’re not going to be looking at them. If one is quieter, get that one.

Also, be prepared to buy a replacement when, not if, one of them fails. It might be years from now, but it’ll happen.

Non-logging? Unbound supports logging.

What shows up on your block log when you try?