How can I make progress on my Minecraft?

I'm thinking of starting a video series for fun, where I try to make progress. It will take some time, so I would like to secure the progress and continue later.

I would do all this on my Spigot server, which runs in version 1.13.2.

Unfortunately I do not really think, what I would have to secure there.

My questions in short:

Where can I find the file where my progress is stored?
When will the file be updated?
If I delete the file and reboot the server, I start again from the beginning or right?

Look in the world folder under "playerdata" or something similar, under your name / your UUID.
When you have unlocked a new Achievement and the world is saved.
Yes.

I'm sorry that I do not answer the question (do not know it anyway) but I have seen that you are afraid of balloons. The same thing happened to me! I would be very happy if you accept my friend request because I'm really desperate…