Hello,
I might be a bit late to this one but I’ve recently released a free ACF addon that somewhat solves this problem. The plugin adds a new Google Map field that basically removes the need for repeater fields when using a Google Map field for more than one location – you can just put all your locations/pins/markers onto one Google Map field. All your locations would be visible in one map on the admin side.
ACF Google Map Field (Multiple Markers):
https://wordpress.org/plugins/acf-google-map-field-multiple-markers
Hope this helps some people 🙂
