
“validity” has to come from the inside tbh, you can’t let other people dictate what is “valid”. if you’re using transmasc to mean “transitioning toward masculinity” then sure it could be an appropriate label. if you want to talk about embodying a queer masculinity without being a man, butch might be/feel more appropriate.
the problem is a lot of trans people see transmasc as just a way to say “transitioning AFAB”, which is gross imo. it also means they try and force that label on anyone who was AFAB and is trans, even if they don’t identify with it/identify otherwise. so when someone who was AMAB asks a question like this, it tends to get a negative response because people are having unconscious biases challenged.
the only thing that i would say is that, this is my personal view, i don’t see “labels” as individual identifiers but as a way to connect oneself with a specific community/history and to be part of that group. so i would ask if you, because of your experiences, feel as if you’re in community with other transmasc people and identify with the history (however you interpret that) of that community? if that’s a helpful thought exercise.