I am not sure what backup tool is best.
At least, I would warn against relying on pg_dump if you plan to be able to recover to a different version. The reason for this is that I reported this issue: "ERROR: chunk not found" and other errors when loading pg_dump from old timescale in which a pg_dump from old pg/timescale cannot be loaded without errors into new pg/timescale.
I have not received any feedback on this which I fear means the backup cannot be relied upon unless restoring to exact same versions 
I would of course be more than happy to revise my position in the event that I receive new information on my post…
For your situation, have you explored PITR?