How did The Shape of Water win so many Oscars?

It was a long time after most other people that I recently got round to watching The Shape of Water. And while it was beautifully filmed from a photographic angle, I cannot understand how such a dire mess of a story gained so much attention and respect.
Even (spoiler alert for anyone who has still not watched this film) the scars on Elisa (Sally Hawkins) Esposito's neck were an immediate giveaway about what would happen at the end. That they would turn out to be gills was the biggest non-surpise in the film! It was so obvious it was ridiculous - and unexplained. And if she was somehow kin to the "creature" how come she otherwise looks so human? And, apart from the gill slits, so unlike the "creature" in every way, apart from having two sets of limbs, a head with the usual placement of eyes and mouth, etc, like virtually every other creature on the planet?
Michael Shannon, an actor I don't particularly care for anyway, gives a phenominally one-dimensional, almost comic-strip portrayal of the jailer in charge of the "creature", pantomime-style in its grotesquery. I must admit that didn't surprise me. It's in line with virtually every other role I've seen him play.
Indeed, for me, this is one of the film's underlying and most common failings - all the portrayals are one-dimensional, almost pantomime in style - and unconvincing. As is the basic plot - which makes me look back with increasing fondness on the comparatively subtler stories and portrayals in the three "Creature from the Black Lagoon" movies of the 1950s! At least in them you could begin to feel empathy towards the "creature" and its plight, something I felt incapable of doing for this CGI version.
So, again, I am left wondering what it was about this film that gained it so many Oscars - and I'm baffled.