Ah yes the old argument of "you need to write a novel to cirtize it"
well then. You better play FATAL then unless youve developed your own TTRPG system.

WRiting a novel takes tons of time, writing one also doesnt make you a better critic. The majority of fantasy out there is either derivative trash, romance schlock or historical fiction written by people who dont want to do research.

In my opinion good fantasy fiction comes not from fantasy novels but from other media, such as games. The fantasy genre lends itself ot visual or interactive media. I cannot say why Science Fiction still produces good new books and fantasy doesnt, perhaps the barrier to entry, at least for semi hard sci fi, is much higher than for fantasy. Perhaps fantasy got a boom and thus its got more trash. I cannot say why it is, but i know what im observing. Even fantasy books that get hailed as amazing turn out to be pretty bad when you compare em to other kind of literature.
and i say that as someone whose not a ltierature snob. I always loathed the ghettoization of fantasy, science fiction and recently crime novels.
None of this is an excuse to be terrible writers.

To get me back to my original point. Whimsy is good. Theres nothing wrogn with it. Tolkien did it deliberatley. It makes somehting feel more like a story, a myth. Fantasy will never be history, it ought not to be, it is better told as myth and legend.