Control arduino via internet (ESP8266 + Neoway M590) (FTP client on ESP8266)?

Question

Arduino

Hello!
I'm worried about this thing:
I have an arduino mega. Several arduins are connected to it via rs485 (they will be connected for sure) on which there is a button (several buttons) and a light. The mega master sends commands to the slaves, the rest respond in turn.
An RF receiver, esp8266 and Neoway M590 is connected to the mega.
How to make mega download "instructions" from the Internet (there will be a site for managing this entire system) and upload data to the Internet. Most of the time, the Internet will be GPRS via the neoway modem + if a wi-fi access point appears on the network and we inform esp8266 (it will also be configured via the Internet) with a password, then the Internet will go through wi-fi.
UPD: since the question was posted, I have only slept 5 hours, and I have come to something myself (without running esp, really).
Yes, the problem is slightly different.
Both esp and m590 will communicate with TCP server or hosting via FTP.
1. In the case of FTP - how to make the ESP8266 be an FTP client?
2. How to make it possible to connect to the ESP8266 directly from a smartphone / computer and steer the whole thing without the Internet? (and the Internet is really "not a lot")

Answer 1

sockets

Answer 2

I generally do not advise doing anything related to the Internet through arduino for such projects, it is better to use raspberrypi

Answer 3

I would not use Neoway M590. And I would take a normal module, for example SIM800C, not for aliexpress.