Hi @JohnnyDataGuy ,
Do you want to display a negative number within a Text Input Box or Label using parentheses rather than minus sign?
I have made a test on my side, please consider take a try with the following workaround:

Set the Default property of the Text Input Box2 to following:
If(
IsMatch(TextInput1.Text, "\-\d+(\.\d+)?"),
"(" & Substitute(TextInput1.Text, "-", "") & ")",
TextInput1.Text
)
On your side, you may need to type the following:
If(
IsMatch(Text(YourNegativeNumberValue), "\-\d+(\.\d+)?"),
"(" & Substitute(Text(YourNegativeNumberValue), "-", "") & ")",
TextInput1.Text
)
Please consider take a try with above solution, check if the issue is solved.
More details about the IsMatch function in PowerApps, please check the following article:
IsMatch function
Best regards,