The real answer is measured in how your actions have affected the lives of the people you claim to be an ally of.
No, this isn’t always practical to measure, but if someone is saying “I’m an ally because I identify as an ally”, I’m certain they have done absolutely nothing to protect/advance the rights of LGBT+ people.
No, indirect action is a form of action, stopping a transphobe from being transphobic is a form of allyship, because presumably, you’ve saved a trans person from feeling unsafe around that person.