Does the choice of the front end technology (Vue, Reat, Ember etc) have an impact on phoenix features like OTP ?
No front end should impact the features of Phoenix (or the BEAM in general). You can pick any front end framework / library you want and you will still have the full power of Elixir. The only choice that may be made for you, is the preferred way to speak to your backend. But you should still be able to do whatever you want for that.