It's worth remembering that on Tapas, the definition of genres leans towards how they might be defined in a more manga sense. So when I think of the "drama" category, I'd probably imagine not just serious historical fiction or say a "courtroom drama", but also something like a Josei manga like "Nana". Nana has a lot of comedic moments in it, but comedy isn't the main driving force in the story, and it has loads of romance, but romance isn't the ultimate outcome of the story either, in fact many of the romances are toxic, tragic or generally don't end well. Ultimately Nana is about the lives of two young women called Nana and their path through various relationships and life events like moving in, getting jobs, pregnancy etc.
The line between "drama" and "comedy" can be quite blurry in stuff that's more shoujo, like there's a lot of both in something like Ouran High School Host Club, which has a premise very much like a Shakesperian comedy and loads of silly jokes, but often veers into serious relationship drama, so I'd call it a "Comedy/Drama". If it had the same tone but a less silly concept and slightly less broad characters and regularly silly setups, I could see it being a drama or a Romance.
I guess the main thing is to say "What is this comic's content about. What does it consistently deliver on?" So if it's about a detective investigating a murder and there's one big chase scene, it's probably still mystery rather than action, whereas if there were frequent punch-ups and shootouts and chases throughout, more like Die Hard, it becomes less Mystery and more Action, even if there's a "whodunnit?" element.
My comic involves magic, so it's technically "Fantasy", has relationship drama, comedy and will have romance subplots, but the thing it delivers consistently throughout will be big spectacle and action set-pieces, so the number one genre is "action". My reasoning is, it's not really fantastical enough for a "Fantasy Fan" who probably wants a more old-world setting and mysticism and fantastic vistas, the main plot doesn't revolve around the relationships, so it's not a Romance, it won't make you laugh every page, so it's not really a comedy (It probably has about as many jokes as most Marvel movies, and I wouldn't call those "comedies").
I would put the second genre as "drama", but it's sort of trumped on Tapas by another category that describes my comic better: LGBTQ+, my comic is consistently queer. It's a comic by a lesbian creator with a look and tone similar to other series by queer creators or with a large LGBTQIA+ following that consistently delivers characters of various usually marginalised sexualities and gender identities, so it's a "Queer Action Comic" before it's an "Action/Drama comic". To me, those are the categories most likely to get it seen by people who will like it most, which is most likely to be LGBTQIA+ people who like shounen manga and superhero stuff.
tl;dr, try to think of what your comic delivers most and revolves around, and decide based on that.
