20th Century Boy and Girl Might look like it has a love triangle but the FL never loves the SML she only admires him as an idol as she is an actress and SML is an actor, she is in love with the ML since childhood and so is the ML and it has lots of cute moments.
Something About 1 Percent They date as a contract so when the contract ends there is a breakup arc but its limited to 1-2 episodes and even then there is no angst or love triangles.
The Beauty Inside No love triangle at all but has some angst because both the ML and FL have their own problems and are famous so need to be careful but lots of cute moments make up for it.
Fight For My Way The FL loves the ML since childhood but takes a few episodes till ML realizes so theres some angst before they start dating but its really nothing major and its really cute.
Healer No love triangle at all trust me it might look like it but theres none
Her Private Life
Lawless Attorney
My ID is Gangnam Beauty Theres some bullying and angst but it depends on how much is too much for you its certainly not Loveo2o but its not a melodrama but you can skip this one
Put Your Head on My Shoulder The Fl likes the SML for the first 2-3 episodes but when she meets the ML in episode 1 she starts realizing that she doesnt really like the SML and that the ML is better.
The K2 The SFL never has a chance lot of people think there was a pairing there but no never so watch it but the main focus isnt romance theres quite some action
Descendants of the Sun They are cute and no love triangle but I disliked this one as they keep getting separated quite often because of lots of other things.
I love cute romance dramas without angst so I know exactly what you want trust me all these are what you want.