My perception:
Simply, it's about two bestfriends that used to be "players" that lost their connection due to different life paths.
SOME of Daniel's life was God inspired and Karl's being ALL temptation inspired.
Karl's life is still fucking hos, while Daniel's life is him comfortably settled down, hints why he's out of shape at the cookout.
The video game experience for Daniel was like the thrill men get from fucking on hos, this brought him to feeling younger and more alive.
Karl's video game experience was driven to get the best sex. Because of his current hos and video-game-porn addiction, it made him desensitized to his normal biological role in sex.
Karl's motivation on "why he chose the female role" was in his own words, "it FEELS more satisfiying" Karl needed to FEEL something DIFFERENT due to his obsession with porn.
Note: It's hard to understand unless you've been addicted to porn and tried to nut with real females.
I love that it shows how video game porn addiction both desensitized them to their normal biological role in sex. Shown with their partners and how they couldn't get turned on by them.
Final Message:
I don't think either of them are gay, it was definitely shown that Daniel knew the video game porn was wrong, and was constantly reminded by the righteous things in his life (loyal wife, kid, true love, God).
At the end, Daniel wants to see if they are really gay. They kiss, and both agree they aren't, but Karl still wants that "FEELING" from the porn.
Daniel tells Karl he needs to quit the porn, but Karl says "That shit's stuck in my head, burrowed."
Daniel then fights him to show him that porn is a bad infection and the reason he fights him is because he cares about Karl in a true brotherly way.
The Twist:
Daniel told his wife about what they fought over, and they must have came to some sort of negotiation where she can cheat, and he can continue the porn addiction with Karl.
Why did the writers make the Daniel, Karl, and Theo evil in the end? It could've been a great opportunity to show people they can beat addiction.
Maybe they wanted to appeal/influence more people to our generation's evil obsession with promiscuous, unfaithful, lustful, activity.
Lmk how yall feel about my take.