If Jack Smith indicts Trump, that could give some states a signal not to allow his name on the ballot in November 2024. Of course that would only matter in close states (he has no chance in some states anyway). In 1968 California omitted the Presidential candidate for the Peace and Freedom Party from the ballot because he was less than 35 years old.
Article II issues (age and citizenship requirements) are a legitimate reason to keep a name off a ballot... bogus investigations aren’t.