Is this the only way to do this? Is there no way to individually change a block within an imported map? When you import a map using modded blocks, the modded blocks turn into a slew of different vanilla things. Most commonly, shulkers and levers, which aren't blocks in the same way a wood log is. The model isn't the same. Sometimes the blocks changed into doors too, complicating things further.
If it's possible to individually change a block within an imported map, I feel like that would make things 100 times easier.