SMO is the server management library. v13 is the SQL2016 version IIRC. Why it would be trying to use that on SQL2019 is a little confusing.
Nevertheless download and install the SMO library for SQL 2016 (I believe it is in the Feature Pack) and try again.
More long term I'd wager that your backup system needs to be updated to SQL 2019 but I'm just guessing here.