Remove the clutch from the flywheel, flip it over, using long nose pliers, pinch the metal ends together and wiggle.
the gearbox just pulls off, again, wiggle
make sure it’s level and not p!ssed or it with get stuck…from memory, lift the prop end to level
It’s probably seized in the spigot bearing. Use prybars….one on each side.
You removed all the bolts yes and have a gap already?