I can restart the chunks processing now, but it's going to be starting from the first topic because I lost track of which topics failed to write. Fortunately it is much faster than upload at the moment - I was actually processing topics from 2023 when I noticed this issue.
Don't run the system all at once!
Make it run in cycles, for example 1 year at a time. This way, if there is a failure in any cycle, you know to what extent everything is fine and you won't have to start from scratch.
You do this manually by running the script in each cycle. Or you can set up the script so that it runs in cycles and keeps a log of the events. Whenever a cycle ends, it informs you of the result, if everything is ok. This way you can follow the process.