Transfer multiplayer server to single player (Minecraft)?

I created a server using aternos and played on it with a friend. However, since he has stopped and I still want to continue playing, I wanted to transfer the world to the single player. The reason for this is simply to avoid the lag and general restrictions in the render distance, etc. Is that even possible and if so can someone tell me how?

For this you need an FTP program like FileZilla. The access data should be in your account. Download the world and save it in the Minecraft folder save. Then you can select and play them in the single player.

I'll try Okey, thank you very much.

What exactly is meant by access data. From the account at aternos? Or which

There's usually a different connection data for FTP than for the account. Just search for FTP data / server or ask Aternos.