Why would they be doing it unwillingly, giving someone hormones who doesn't want to or is unwilling to take them is grossly unethical and violates their bodily autonomy and their dignity. If they aren't willing it shouldn't be done at all.
For people who will say that they're "in-denial" I just want to say that self-determination is very important especially when it comes to something like gender transition and trying to take that away from them is disrespectful to them and even psychologically harmful.
It really does depend on the Lore and/or species of dragon within the lore.
Some are hermaphrodites, meaning they have both pairs of sex organs.
Some are asexual, and thus don't really have gender, they might be seen as female since they would bear similarity to females of sexually reproducing species but it isn't the same and they likely would not have the roles and behaviors associated with gender.
Some do have gender and are sexually monomorphic, meaning they look the same and develop the same regardless of their sex/gender, only difference is their reproductive organs.
Then there are ones that are sexually dimorphic and have great differences between the sexes and how the develop, differences such as size and strength, or colored markings, or both.
Out of these only the last one would benefit from hormones, and even then it would depend on species.
All of this assumes that Magic or shapeshifting isn't on the table, if it is this all goes out the window because they're no longer restricted to how their bodies are formed and basically have full control of the gender, sex, and species they choose to present as. Most of the stories I've seen the dragons have either full or limited shapeshifting abilities.
I believe they are in pretty much all lore but they are inherently magical creatures that are able in some lore to change their outward appearance completely.
I've seen where they are asexual which is pretty close to not being gendered, but many times they'll still be referred to with gendered pronouns, despite not really having gender due to being asexual.