RTK radio without Line of Site

What kind of range can i expect from a radio base station without a clear line of sight? I’m currently running an F9P using the WiFi hotspot from my phone and pulling corrections from my local DOT CORS network, and very happy. However i’m building a 2nd receiver to put on a friends sprayer and worried about cellphone coverage. In the last few years with the switch to 5G we’ve been having a lot more deadspots in some fields and has me worried about using the CORS network.

His farm is located ontop of a hill that is higher than all of our fields, and there is a 40ft tall grain leg we could mount the base station on to get it well above any tree’s or obstructions. Most of his fields are down in creek bottoms surrounded by tree’s, and a little hilly.

A majority of his fields are within 5mi/8km, and mine are 15mi/24km. Is it possible a radio base station would work well, or are we better off to continue with WiFi hotspots?