Does anyone have any ideas?
If you think you "should" be a melee character because nobody else is, then you are a fool. At least some of the other players choose their PC freely without knowing what class the others were going to be, so why should
you get the shaft and be morally forced into a limited choice? The game works fine without all traditional roles covered, the party will adjust itself to whatever composition, so just make up a PC you want to play instead of worried that it's up to you to do community service for the rest of the group.
I won't believe that with 12 classes and 30+ subclasses there isn't a character archetype that doesn't attract you into play

Either choose one because of the narrative or because some mechanics makes you feel you'll have fun playing it that way.
It also always helps a lot to recall some cool character from a movie or book you have recently watched/read, and try to base your PC around that. What was the last fantasy/sci-fi/action movies you've seen? Wasn't there some cool character? How could you transpose that character into the fantasy medieval-ish style of D&D?
And if you really really have no clue (but normally that happens when you have
too many cool ideas to try) there is always the good old gamer's friend: the
die. Roll a random character

Roll class, race and background at least... or roll everything if you dare!