I would say Hunky Dory I’d skipped is next. Then I would follow him chronologically up to Scary Monsters, to watch the twists and turns of his glory years in real time.
For Bowie, most people take a different path and find their own journey. If you liked Ziggy, Aladdin Sane is better. If you want to venture onto a different side of Bowie, Scary Monsters is fantastic, and has some familiar songs (Fashion, Ashes to Ashes). If you want to stay on the earlier phase, Hunky Dory is a must. More experimental, Station to Station. Ambient/instrumental, then Low or Heroes.
A year or so after DB died, a philosopher (w/ an interest in utilitarian ethics), statistician, and neuroscientist/cognitive scientist from M.I.T. did a DB study. I believe the statistician is a big fan and the other two joined in for fun. It is more a fun thing, but still approached academically. Anyway, they looked at his entire studio album discography (no live albums, comps, etc.)...
...They came up with the "best" (w/ allowances for variation per the individual but I think meant to fit an overall mean) order in which to listen to his albums to best understand his overall artistic vision and musical legacy.