I made a mistake is there any way of saving my fish??

i was having algae building up after my otos died a few weeks ago. the snail population was getting lower cause of the assassin snails I got to take care of the huge infestation. my cousin told me to use vinegar to clean the tank algae and do a water change so i went home and emptied about 30% of the water before adding the vinegar. then filled the rest of the tank back up (32.5g)

when i got up this morning my four bettas were near the bottom and not swimming but still alive. so i quickly moved them into a smaller tank i have but i think one or two may not make it?? im now realizing i think my cousin meant that im supposed to take the fish out but he’s not answering his phone

my snails aren’t moving much either. i took about half the water out and replaced it again but it still smells a little of vinegar.

is there any way I can save my fish?! should i take the plants and rocks out to wash them now too and maybe the gravol