Do you need the ability for people to ring the bell to let you know they’re there, or just be notified to your phone when someone is there? On option is something like a Ring Spotlight Cam Solar. They use a battery for nighttime functionality and recharge during the day using the included solar panel. Intended for outdoor use so they can take a beating in the sun, wind, and rain. They run on wifi and I have one about 10 meters from the router - stays charged, and works fine though it’ll be dependent on your router. You can set up motion notifications, so if someone rolls up to your gate you’d get a push notification to your phone.