[Question] Interested in getting feedback on my build! Newish to DnD. Let me know?

Im building a Dex-based Echo Knight, Bugbear. Starting at Level 6. I imagine like a combo of Chewbacca. Using a rapier as a weapon, but flavored as a boar hunting spear so I can fight like Oberyn Martell from Game of Thrones.

I rolled two stat blocks.

17, 15, 12, 11, 10, 7 - kept this one cuz a 7 in something is funny.

16, 16, 12, 11, 10, 10

But if there is math here that works better for the other stat block, let me know!

I threw 17 in Dex, added +2 to Dex, then got it up to 20 with Piercer ---- Is this dumb? Not sure there are many items that increase Dex. And I'm always afriad the DM will make me 'lose' items lol

I took Dueler as my fighting class but open to Superior Technique and Tripping.

I threw the 15 in Con and added +1.

I know there are very few ways to increase Con in game. Con modifier impacts how many times I can use Unleash Incarnation for an extra attack from my Echo. Is it worth spending points to get my Con up to 18? 20?

Sidenotes: I am permitted 3500 gp worth of items cuz I am joining late (Level 6)