What should I do with Asia Minor?

[konny]

Would it be worth giving Hallikarnassos and Side back to the Ptolemies to keep things messy there? Northernmost provinces will go to Pontos and Hayasdan, I think.

Yes, that's what I would do: give these lands to AS enemies in return for a treaty of alliance. That way I once secured my Northern border against my Aedui and Sweboz enemies: gave provinces like Aventicos to the Arverni in return for an alliance. That held for many decades, prevented Arverni from destruction and pushed back the brown flood.