I don't think they are acanthus leaves either.
I think they're kind of like Myosotis leaves (perhaps supposed to represent Myosotis leaves?) and in the French enamelled 1820s glass that was indeed what they were along with little forget-me nots. Also in Bohemian glass a similar motif in that period.
https://plantatlas.brc.ac.uk/plant/myosotis-scorpioidesBut I still don't think that puts your jug that early. Difficult one.
Perhaps it is later 1800s whilst the transition from top down to bottom up handles was still going on, and when amethyst colouring could be bought to use?
The rim is very unusual as well. Is it cut into those scalloped shapes? All that cutting does look as though it could be Bohemian.
Just thinking of other possible makers you could look into that aren't Bohemian:
St Louis
Baccarat
Val St Lambert
American? - I know nothing about American makers at all.