i realize r/plumbing probably gets clogged toilet posts every day but...

i can't figure mine out. it's not like my toilet is clogged. it's... semi-clogged? it still flushes, but first, the bowl fills up with water, almost to the brim and just before spilling over. then, it will drain down but very very slowly.

is something stuck in there? i heard i should use hot water and dishwashing liquid. will that work?