What was the main barrier to acceptance by the scientific community of Galileo's heliocentrism?
Well, there's a few things to unpack here, not least of which is that none of the heliocentric models at play were Galileo's. More can always be said on the matter, so if anyone would like to make their own writeup about our favourite grumpy old Tuscan disputant; for the meantime, we do have some previous threads covering that kerfuffle about the cosmologies:
Some bonus restricteddata on related matters: