I would save Diamond Weapon to counter their Kan-E-Senna.
I would place Kan-E-Senna to take Estinien or in the bottom middle if he's played first. If not, then I would usually play in order with Asahi in the bottom right and Kan-E-Senna following in bottom left to take theirs. Hilda or Lyna in the top available corners to secure their spots and from there it should work out.
I eventually got a good win rate. Then it's just rng for the card. Best of luck.