please correct me if i'm wrong ,
maybe by increasing the difficulty to a higher value by using (if pool support it , for example) "D=512000"
Then the miners will send out less data (less frequently)
There is no need for this, most pools will auto adjust the difficulty to what you can actually deliver, be it hashrate or bandwidth. Forcing it usually leads to a worse (suboptimal) situation, let the pool do it for you.
I still don't understand why powerful 4G antenna + support construction wouldn't work in the location?
You can use
4g here (sometimes, lol) and when it works, it goes really fast. But they cap it to like 1g of data per month so you can empty it in like 1 day watching youtube. Then it stops entirely. A couple of the companies (there are just 3) charge you per byte after that. The third is State owned and is a weird mystery. It would be too complicated to explain, you can't even tell what data plan you have, and new customers are not offered data plans at all (everything is metered by the byte, and expensive).
Most likely there is no
4g coverage where that setup is. In many not so well developed countries, mobile data coverage is... random. Maybe no data but phone, maybe data but the slower one, maybe
4g but after an hour it switches to the slower one, or leaves you without data until you reset it...
And here sometimes you can even get 4g link but no internet, because they have problems upstream as well...