I didn't say it was hard, I said it was bollocks.
But it isn't bollocks.
I get that there might be times when you are in a society that doesn't accept certain beliefs as as valid as others, and that you might go along for the sake of acceptance. But the idea of 'authentic self' goes beyond that and supposes that your belief is inherently fixed. You might as well argue that political beliefs are fixed.
Again you are spectacularly (or deliberately) missing the point.
Being your authentic self is about accepting your genuine thoughts, feelings, and behaviours rather than pretending that they are something different. It doesn't indicate in the slightest that your genuine thoughts, feelings etc cannot change over time, merely that you accept those and don't pretend to be otherwise.
So let's try another (rather more mundane) analogy - imagine I hate opera, but pretend I love it (because I regularly am expected to go to opera with real aficionados and want to fit in). If that were the case in a somewhat trivial respect I wouldn't be expressing my authentic self. However over time (and exposure) perhaps I would genuinely come to appreciate and love opera, in which case I would have changed my mind and my expressing my love for opera wouldn't be pretending so would reflect my authentic self.
Now I know this is a trivial example when compared to belief in god or sexuality.
But my own experience is that I never really changed my mind about believing in god - I never really did when I had any kind of genuine capacity to think about it, even though for a while I kind of kidded myself that I did believe. I didn't change my mind - I moved from not being the authentic me (in relation to god) to being the authentic me.
Now I'm not gay, but I think that many gay people recognise that they were always gay, even if they spent quite a bit of time kidding themselves that they weren't (hence we talk about people 'coming out' not 'changing their mind') - so in that case when pretending not to be gay that person (in relation to their sexuality) they would not be being their authentic self, but having come out they would be being their authentic self.
But none of that is to say that your authentic self is constant, fixed and cannot change, but that how you express your beliefs, feelings etc is genuine and not pretending to be something you aren't.
Again, not rocket science and not bollocks.