Tutorial on archiving Custom Report?

Does anybody know a good tutorial on how to archive Custom Reports?

What is it you are looking to do. When you talk about archiving custom reports, are you referring to importing different log files into different sites?
Please clarify.

I noticed that the report I made myself is calculated anew every time I look at it. Sometimes (at times with a lot of activity on the site) this leads to an error.
Now I was wondering how I can archive it so that it doesn’t have to be recalculated every time - like the reports Matomo comes with by default.