had upgrading the bandwidth of the already present RF link or doing a microwave ptp link on your own any part in your prior research?
I might have to build towers at both ends to run in a licensed range, eg: 11Ghz, and even there there's not good access. So I might still have to pay 20-60k to get access on top of the 5-10k for radios and registration of the licensed link. That easily builds 1-1.5 miles of fiber, and since I was just over 2 miles away from it, it became easier to just do that and have something reliable.