well, their are quite a few differences !
explanation:
first difference is a main sequence star is made of carbon, while a neutron star is made of neutrons. another difference is a main sequence star still has hydrogen to burn, while a neutron star is a remnant of a supernova.
a main sequence star is what’s left over from a low-mass star death, while a neutron star is what’s left from the death of a high-mass star. main sequence star and a neutron star are considered the same thing, except a main sequence star spins.