My partner has seen the OT and sequels but never the Prequels or Clone Wars, so we've been watching the series in chronological order, going:
Phantom Menace (Hal9000 edit)
Attack of the Clones (Hal9000 edit)
two edited special episodes of Clone Wars (2003) to introduce Anakin becoming a Knight, Asaaj Ventress and Grievous,
then Clone Wars (08-2020),
and then the sequels (Hal9000 edit).
Right now we're on Rebels and it's been a blast.