Is there any kinda option to do that (not to download files everytime)? or how does it work? Whatever server I try - it takes 15 minutes minimun (
You can disable downloading music, textures, and sounds.
I say disable sounds, and music, textures you would need just in case, music is pretty optional and not a whole lot of people use it, unless it's a music genre server, same goes for sounds. That should cut loading in half.
If you have free time to spare, join the biggest file hoarding server. When I host, and people say it takes forever, I tell them that once they load my server, every other server out there will load fast, seeing that I had like every mod that every other server had.
That or download mods, even if you don't use them on your server, they cut loading down. Weapons, vehicles, and maps, are the biggest files to load.