If you kill more than 20 players, it repeatedly shows an "x20" icon in the bottom right corner for each additional kill. Are there no icons for higher numbers?

Also, the streak sometimes randomly resets without a death, or even getting hit. Not sure what that's about.

Yes we stopped the x# icons at 20. We hoped this would never be necessary to have a higher number
About the streak "reset" I might have seen something like that in a youtube video hmm.

I can confirm streak reset in dominance sometimes. But no idea why it happens.

Hah! Well, "luckily", the streak reset bug makes it pretty hard to get > x20 .