This is too vague. Reinstalling Duplicati rarely fixes anything because usually the issue is not its install. Database issue can sometimes be fixed by recreating the database from the destination files, however destination file loss or corruption is hard to recover from. Do you have a specific issue type to discuss?
Some of the answer given (comments on configuration) are for disaster recovery from loss of computer. Configuration is only kept locally unless you copy a job export somewhere to ease return to normal use.
Exporting a backup job configuration makes it easier to get back to your previous backup config routine.
Restoring files if your Duplicati installation is lost can be used for emergencies. It still needs some data from you that you saved somehow (examples were given) but it doesn’t need e.g. the source file config.
If you’re doing planned server rebuilds, it’s probably faster with less risk to copy files locally beforehand. You can even copy the databases instead of importing configurations and recreating the job databases.