1 sounds like you have a rocky relationship with a 20 year old. I’d recommend keeping the irresponsibility and bisexuality separate. You need to cut strings financially. He needs his own space to learn and fail, and to buy his own insurance. Not, pay mom and dad but actually be independent. And yes, he may not be responsible and get car insurance and he may lose his license. That may have to happen without your interference. If it’s your car he is driving, remedy that.
2. It’s wonderful that he has direction and passion in one aspect. His acting. You should support that and be proud of his skills and accomplishments. This is the area in which you should forge your bond and keep the relationship healthy.
I don’t know if you mentioned if he is living with you or not but if he is, it’s your right and parental responsibility, yes, even at 20 to ensure your house has rules, no guys or girls, spending the night etc.
3. While remaining supportive do not engage in pride or LGBT events with him.
4. The “your choice” comment was unfortunate. It invites defensiveness. He must know your disapproval so hounding it is unproductive. Ignoring the LGBT normalcy comments and politely changing the subject is the way to go.
5. You virtually leave out your your faith life and His in your information. Why? Is he involved in Church? Did you live a faithful household growing up, praying together, discussing the faith etc?
6. Get your behind to adoration. Do this often. Have a schedule!