HDD-access speed during backup suggests setting changes if you want less speed loss from backup. The tradeoff will probably be backups will take longer to finish. You can decide which you’d rather get.
A rather recent option is –usn-policy which will save Duplicati from having to scan backed up files for timestamp changes. You could also try –tempdir to put temporary files on a RAM disk, and if you lose them due to a Windows crash, it’s probably no big deal. You can find RAM disk programs that save to persistent storage at proper Windows shutdown, but I think you lose if the PC stops in another way…
Backing up at least Duplicati-server.sqlite (which has the backup settings) is a good idea for safety, or you can export individual jobs. One advantage of that is you can better encrypt the secrets of the jobs. Having such backups will make it less of a disaster if you lose the laptop or its drive, and might make using a RAM disk with a save-on-proper-shutdown tolerable in terms of pain from improper shutdown.