There are frequent comments -- not necessarily here -- that there are only a few plots, endlessly recycled. Some critics will even list them for you.
What these are are lists of plot types. Maybe any plot will fit into one category on the list (although I'd like to see them fit Heinlein's "All You Zombies" on some list.}
Two plots in the same category aren't the same, or even almost the same, story. I've been reading a book of 50 (presumably great) short stories.
After all, the tags say that there are only 6 types of character: Adult male, teen male, boy, adult female, teen female, girl.
That doesn't mean that you can't have many different characters. If someone writes a story featuring Jeanette Brennan with a different name and I see it, I'll complain to Lazeez.
I, at least, seldom start with a plot, let alone a plot type. My usual starting point is:
1) A guy,
2) A gal,
3) A situation.
Now that formula doesn't cover MM or FF stories. It doesn't even cover all my stories. Still, you could write all your life following that formula without repeating.
Sometimes, when you start like that, you find that the guy and the gal don't interact in a way that leads to sex or not in a way that leads to a story. You have to be ready to abandon your beginning and begin an entirely different story.
A few caveats:
A physical description isn't a character. Characters aren't as complicated as real people, but the closer you get to that, the better.
You have to know more about your characters than the reader does. You only tell a little, but as the story goes on, the character acts out of your understanding of him/her. That way, the reader sees something consistent.
With a serial running right now in which the guy and the gal meet in the first chapter, I can't say, "Don't have them meet onstage." Don't restrict yourself to that, however. "Situation" doesn't mean "The circumstances under which they meet."
One reason that I like to write about married couples is that a marriage involves lots of situations which involve sex. Even if the situations don't, the couple often have sex.
I say you start with a situation, but -- really -- you start with a situation, one or both characters react to that, and that gives you a somewhat different situation.