I'd say no it's not necessary, generally. Some stories like LotR have almost no romance in them but the books resonate with people because the themes it plays with are just as big and just as meaningful. Which isn't to downplay romance though! Falling in love is one of them most universal and relatable experiences which humans share worldwide. We all know all the feelings of happiness and sorrow related to the topic. Actually, I've kept my stories kinda aromantic most of my life but since I got closer with my gf I've wanted to write more love stories. It just has that kind of effect on you.
As for smut, I'd say less is more. many comics shoehorn it in unnecessarily and it just kinda makes me roll my eyes and move on most times.