I'd go Twilight 6 / Stars 3+ with 15 or 17 con and 16 wisdom, and the resilient con feat, if you can arrange those stats. Wisdom is still your primary stat but as a summoner you can afford to delay wisdom a little bit.

The combination of the twilight sanctuary's temporary hitpoints and the dragon constellation's all but unbreakable concentration will make your summons incredibly hard to take down, while also buffing your allies. With this setup you can use both the channel divinity and the constellation twice per short rest.

Side benefit; this build can fly really well, with the ability to fly as fast as you can walk a number of minutes equal to your proficiency, and eventually a flying speed of 20ft whenever you're using your dragon constellation.