I cleared the star chart, finished every story quest, maxed out open-world standings (except PoE), maxed out syndicates (New loca, The Perrin Sequence, Red Veil, Steel Meridian), and killed Archon several times.
I genuinely don't know what to do from now on. Every other weapon feels like a downgrade of incarnons. I'm unsure whether I want to farm other warframes and do that tedious forma routine again.
I guess at that point for me, it was collect everything and reach MR30. Max out every Syndicate, collect every free Operator cosmetic, every arcane (still working on that), etc.
Warframe is a game of farming, so I set farming goals.