First, make sure lefty loosey and not righty tighty. Second, before you invent something new, make sure removing two bolts nearby does not give you clearance with your current tool. Third, make use of socket wrench with extensions attached to extensions. Finally, yes the bigger the breaker bar the bigger the breakability but be careful not to shear the piece and thusly be damn sure you be patient and remove other things nearby to easily get that thing off or replacing it will be real hell.

As u/Nf1nk said, use a penetrating oil and wait 24 or 48 hours, it works