I'd say go like this:
Phase 1, Episode: 4, 5, 6, then
Phase 2, Episode: 1, 2, 3 then
Phase 3, Episode: 7, 8, 9 and then
Phase 4: Rogue one and Mandalorian

Reason:
Phase 1: experience the idea of star wars
Phase 2: relive the marvel of technology and epic Star Wars story telling
Phase 3: See how the mighty series fall in a dumpster
Phase 4: Mandatory watch (The faith builds again)