Your whole mindset seems messed up. Stop idolizing the girl. That's why you're in the friendzone. Find a girl who is single and invite her to whatever (harder during the lockdowns). Why focus your energy on a girl that's already taken? It comes off desperate. Like that was the only girl you see yourself having a chance with. And deep down on some level that's how it comes off to her as well. Think about it, she'll never tell you in plsin words or admit to it. But she knows you are single. She knows you know she has a BF. She knows she's not giving you any real action. She knows that you know she is getting fukked every other day by her man while getting free time and energy from you. And she knows you are not fukking anyone else.
Trust me, she sees you as a lame breh. I'm not even trying to diss cause we've all been there. Now you're on here asking for help on how to get her. There are ways to get her but i suspect it's not gonna work for you because the game is not in you. It's like if micheal jordan wrote a post on a messageboard explaining how to dribble, pass, etc. You're not gonna be able to execute flawlessly just off reading. You're seeking shortcuts to the game because you don't respect the game and think you are above the game. Yet you expect the game to provide for you...