I feel like external pressure is only half the problem. It is important but IMO the role model is also a problem. Non toxic masculinity is often describe in the negative of the toxic masculinity : you're good when you are not toxic, not when you are something positive.
In some way it is less restrictive, but in other way it is missing the model.
The other side of this coin is the corruption of the ideal that lead to nihilism. Toxic masculinity corrupts ideals. Violence is strength. Protecting is necessarily the destruction of the threat. Independence is power. Smart is manipulation and deception. Everything is to be seen through a lens of domination and power. And that is the core of the problem.
Instead, a model is to be seen with any quality, but through another lens. Strength can help the weak. Smart can disarm an explosive situation. Power is to be shared and used wisely. Basically, a model opposite to the toxic masculinity can be many things with all the qualities of the virility, but the difference is that they will be used and targeted differently. And for many people, it is to be learnt through a model.
This is a core problem because for many people, if you tell them to drop the toxic behaviour, there will be nothing left to aim for, nothing for them to transform into.
And this goes back to the social validation you're talking about. Going from toxic to positive requires a transformation so that the qualities someone has can be positive instead of negative, but as qualities they can still be praised and admired.
My problem with this is these new qualities are just as likely to be used to build a toxic hierarchy. The problem seems to me to be not just the qualities themselves but the competitive nature that is more or less beaten into boys at a young age.