You have to stick up for yourself or nobody will.

Whenever someone starts to diss you, calmly disagree, say that it was a rude thing to say and that your beliefs and sexual orientation are none of their business, then leave the room.
Don't pay any attention to them or even look at them unless they are acting positively toward you from then on. Just get busy and happy and never talk to them or about them..act they don't exist.

This quickly trains them to leave you alone..two weeks tops. I straightened out my parents from attacking my children after about three times of doing this. Whenever my dad started accusing them of something, I'd say "Look at the time! Gotta run! Love you!" then we'd leave.

After about three times of doing this, my mom would quickly shush my dad every time he started in on them.

Sorry, no words of wisdom here...
You can choose your friends, you cannot choose your family.

I am sure you have friends aplenty here if you wish all of whom will gladly be a shoulder to lean on if you need it.

I'd suggest that you keep your lack of religion and sexuality to yourself and not share it with other family members. Pay lip service to their religious beliefs and homophobia, so that your life is less troublesome. Hopefully, one day, when you are free from the constraints of your family suppression, you will be able to sing your views and sexuality from the highest hill and nobody will judge you poorly for doing so. Good luck. ?