I think it’s even far simpler than that.
This isn’t really a tinfoil because it just makes logical sense but, I’m gonna say her interest in Islam came directly from Rody. They were friends for a while before she went full yandere on him.. so the Saudi globe thing is just something she made up to make it look like she’s sane.
When he rejected her and she threatened suicide, he suggested she turn to religion and of course she ‘chose Islam’ in the hope he would one day reciprocate her feelings.
But because Miranda is a full blown narcissist she can’t let go and admit defeat, it’s gone too far and even though I have no doubt she does not believe she is Muslim, she believes her own lies and enjoys the power of ‘being pious’.
I really want her to fuck off to Saudi cause she really will have to behave in the way she pretends she already does, but I’m confident she isn’t married to a Saudi because it would be illegal.