Url Request instead of Server

Hey there,
so I have the following question:
I have developed a multiplayer game that runs for Android and IOS platforms.
Actually, I’m very happy with it, it all works and I’ve been playing with friends and other interested people for some time.

But before I want to publish it, I would like to know if it is really “professional” and later, I will not get insulted by angry customers.

Instead of a server, I only use a URL-Post-Request which queries the game data every 2-3 seconds.
Since the game does not require any reaction speed and it’s more of a turn-based game, it works that way too.

I first thought of integrating Firebase, but since this is only installable through third-party plugins, I’d rather stay away from it.

I would like to know if the data download volume is much too high for the end customer. And so I need a dedicated server?
Is there a way to save the amount of data downloaded and print it out in the form of a log?

Four players are constantly asking for data every 2-3 seconds via a url request (“www.url.com/getgamedata”). With these data, the local game changes.