GEPRC - MARK4 LR10

The budget is not enough. I would look for something like Holybro X650, but it's way over your budget. Don't use 4in1 ESCs in heavy load drones, because every crash means something is going to burn and replacing one beefy ESC is cheaper. Motor max curent draw does not really matter for long range, your target should be 70 % throttle at max. I did 1 kg payload on GEPRC LR10 at 2 kilometers on 6S3P Samsung INR21700-50S batteries, but it was not very pleasurable flight and it was risky - it is 2,3 kg without payload, only battery and drone. You do one wrong stick move and it does not have enough power budget to fix it. Fixed wing is much more efficient for cargo, but you have to solve take off and landing - look at the Zipline company in Africa, what they do is incredible.