I wish my browser let me do this by default. Rather than "let this site know your location?" it should be "select a location to give to this site".

(I'm sure there are extensions and/or developer options that do this, but it's the default I want)

You can set latitude and longitude after opening settings with the gear icon.

you can use my version sunsignal.app and enter a zip code.

Seconded.

I'm certainly not giving my exact GNSS coordinates to any random scrote who askes for them. Frankly I'm amazed some people do this.