(Major Spoilers) Main Couple Gets a Happy Ending

This is a bit of a cheat because the leads are not in a romantic relationship and haven't even confessed their feelings directly (except via song / naming a song) by the end of the drama (thanks Chinese censorship), but the end implies that they might be about to confess their feelings or at least will be together going forward and it avoids the bury-your-gays / historic dramas must have tragic endings tropes so it's worth including here I think.

Although in the end the leads are still basically dating with the FL living a life of a (happy) commoner outside the palace and the ML living in the palace as the emperor but working on making it possible for them to be together openly.

Very bittersweet ending for the SML

Episode 3 - 5

Although the ML goes to school in the countryside far away from the FL, they continue to date and visit each other on weekends.

In the very, very end.

Very short WLW mini web drama.

Technically she only asks him to be in a relationship in a roundabout way at the end of the drama, but we know he will accept.

Slightly open, but they defeated their enemies and survived

Maybe slightly open, since they're still in high school when the drama ends

It's not entirely sunshine and roses and some viewers found it frustrating, but they are portrayed as being fairly happy / content.

Sad ending for the SML though

They don't actually resolve the underlying problems in their relationship, but they're together and happy about it / happy in general...