What is the meta for storage on multiplayer servers?

I almost never play multiplayer but my uni has a minecraft club with a server i’m in. I want to be at peace of mind with storing my things. I know there’s no 100% safe method, but I am skeptical about just putting it underground since I remember there was always a way to track people down whether it’s chunk loading or pie chart or whatever. Bases as well.

I guess i’m asking, how do you prevent getting raided while offline?