I had an idea on this. I'm not sure how practical it is for your usage case, but I was able to achieve the desired effect by moving the alarm to a derived tag or an expression tag.
Example:
Actual event value = 82.687545776
Tags:
TestTag01 has the raw value and TestTag02 has the expression value
Expression:
round({[.]TestTag01.value}, 2)
Result:
Both alarms have the same trigger value, but TestTag02 displays with only two decimal places.
Here is how that looks in a derived tag:
