( java ) I cant seem to find the backup files for my server.

I managed to re-open a Minecraft server my friend had years back by receiving the files from him. I struggled a lot to port-forward because my Internet Service Provider apparently doesn't allow port-forwarding so I've managed to find an alternative; tunneling. I used playit.gg to run the Minecraft server to allow multiplayer to happen.

We've been playing for a couple days now and had ran /save-all successfully. The server's been turned off and on and what we have been building is all saved so no issues there.

It's come to my concern that there is no way the backup the server. I've checked the folder "backups" and "saves" and visibly, there is nothing there even after running /save-all. I have tried watching YT videos and most show that you just go to SinglePlayer > Backup > etc. I can't do that, I can only go Multiplayer and thats all due to me being a local host with tunneling.

I'm thinking of trying to save the file of what we have now but then find a spigot to run the server instead so I don't have such a hard time like this. What should I do in order to save the server files?

TL;DR: I cant find the save files for my minecraft server. I need help finding it.