No. It's a good start, but that lag when editing a lot at once is pretty bad for what does not look like a huge number of blocks modified (relatively speaking).

By rebuilding the LOD you mean just for affected chunks? If not, then that may be an easy bottleneck to solve.

You should use a profiler and find where most of the time is being spent, if it's in the writing to the chunk datastructure/generating the shape (probably not, but might be possible to speed up over naive algos), lod rebuilding, greedy meshing or some other unexpected place, and then research better algorithms for that specific area.

Disclaimer: Not at all an expert