I saw someone recommending it on TikTok but I never got to search it up and I can’t remember the title. The main female character was blonde, there was a black haired guy and also a blonde one dressed as a prince. Apparently every time they try to commit suicide they exchange bodies (the female lead and the black haired guy).
This is likely What It Means to Be You. The theme of suicide and the character descriptions match. The "blonde male prince" is probably the female lead's younger brother, who appears in the first chapter.
This is a brand new series so I can't confirm that they switch bodies multiple times, but novel spoilers I read do suggest that the series involves multiple suicides.