Pi Zero - Point to Point (with repeater in the middle)

[Naacho]

Hi,
I want to install a wireless link to carry a high speed internet connection (300 + 300) from one remote location (A) to another (B) saving a hill between them that prevents the link from being direct (Line Of Sight).
On the hill I must install a solution that repeats the data/signal (RPT) from A to B.
- A to RPT: 4 km (LOS)
- RPT to B: 2 km (LOS)
I would like to use a low power sbc and dual band (2 + 5 GHz) high power simultaneously MU-MIMO ¿ac? USB dongles and high gain antennas.
Initially the internet connection will be taken from existing public wifi network and in the future from a router.
Please:
- Can I do it with Raspberry Pi Zero (not W)?
- Can I do it over USB 2.0 or would it be necessary 3.0 USB adaptors?
- Can Pi Zero handle that speeds / throughput?
- Can I connect Zero to a GB router instead?
- What usb dongles do you recommend?
- Which must be A, B and RPT configuration?
Best,
Nacho