Also, I don't know if what Apple is saying about "crowd-sourced" is 100% true. I mean, we have to assume it's true. BUT, I do know that I live out in the middle of the boonies, and it knows exactly where I am.
I also took the time to register my publicly-facing static IP addresses with the main services that companies reference for GeoIP location:
https://support.maxmind.com/geoip-data-correction-request/
There's at least one or two more out there, but I can't locate my last registration run email.
If you pull up the following URL on your home network, see what it says:
https://www.maxmind.com/en/locate-my-ip-address
Is it registered? Is it even close?
If your public IP address is a static IP address, then you can register it. My IP address links to my house. Which is probably scary? 😁
If your public IP address is a DHCP (changing/dynamic) IP address, and it changes often, you could just keep registering each IP address that your router is issued with your home coordinates. That won't help the next guy who lives elsewhere and gets your DHCP address afterward but...yeah. It'll maybe get them closer than your ISP's HQ?
Hope this helps?