Thanks for posting to the Avenza MAPublisher Forum. To the best of my knowledge there is no way to automatically adjust/set this distance. A user can go in and manually move the leader line or label but there are no settings where this can be specified and implemented in an automated fashion. By double-clicking on the MAP Tagger Tool all the possible settings are displayed.
Adobe released an update to Illustrator 2021 (v25.3) that includes native support for M1 Devices and Rotate Artboard functionality. Please note these features are not yet supported within MAPublisher at this time. See compatibility notes.