How the type system responds shouldn't change because it's not actually true. The % operator still returns a number but only on some PHP versions it throws a deprecation notice.

So just change the rule please. The condition should be written differently.

1. Please verify that all the X from table here Catch implicit conversions in mod operator #2466 are reported with 'Binary operation "%s" between %s and %s results in an error.'.
2. Please write tests that all the D are reported with 'Deprecated in PHP 8.1: Implicit conversion from %s to %s loses precision.'.
3. Please note that types can for example be int|float or mixed. You should be able to take advantage of RuleLevelHelper so that something that's always wrong like int % float is always reported, something that might be wrong like int % float|int is reported on level 7 and int % mixed is reported on level 9.

Please see how RuleLevelHelper::findTypeToCheck is used in many existing rules like InvalidCastRule. Basically there's a callback that checks the type and transforms the type based on the rule level. Then there's $type instanceof ErrorType with early return and then there's the callback called again on the transformed type.