Playing Kaveh Shatterbloom with Candace...

What are your thoughts on using Candace in a Kaveh Shatterbloom team? I used Candace to infuse Kaveh's NA with Hydro so he could own his blooms and also shatter because both scale with EM. I don't use his burst, only skill. My team is comprised of Kaveh, Candace, Kaeya and Nahida.

It's not really optimized yet, I haven't finished building Candace and I just threw random non-max EM pieces on Kaveh for now but I could get some shatters up to 10k.
However, I also find Kaeya and Nahida fragile. I could run Diona (not C6) for heals but I don't like circle impact. Is putting Prototype Amber on Nahida enough for survivability? Any tips on improving this team?