Shitty best friend is the one trying to take the male lead's girl

Any where the male lead's best friend turns out to be a piece of shit who goes after the female lead even though they like each other. The best friend tries to get in her good graces and then slowly tries to tear them apart. Maybe he succeeds and starts to date her for a bit, but in the end the male and female lead get together/get back together.

Like Hana Yori Dango (Boys Over Flowers)

I can't think of any dramas that fit exactly, but maybe try:

• Princess Agents - they're not exactly "best friends" (warning: this ends with a cliffhanger)
• Jealousy Incarnate - honestly the ML is the jerk between the two of them imo
• Sassy Go Go - the best friend isn't a total jerk, they just both like the FL
• Hwarang - the SL is at least as much a rival to the ML as he is a friend
• She Was Pretty - the FL's best friend helps her but then deceives her and goes after the ML (what you're looking for, but gender swapped)
• Heirs? - it's been a long time since I watched this, but from what I remember it sort of fits
• The Imperial Doctress - it's complicated but sort of fits

• A game about love
• Can you hear my heart