To prevent lag make the hitbox of it a full block and make it toggleble by a command. Sculpted blocks will turn into a normal white concrete block if not enabled

Im telling you rn that this would cause immeasurable lag, to do this you need to use display entities which is all when and good, problem being those display entities get very laggy and ram intensive for the server at around 2k-3k entities. Which would be 2-3k of your little blocks. So the server won't be able to handle this if everyone's using them.
Secondly and probably the bigger problem is with lag, if someone wants too they could stack plenty of these in a very small space in 1 chunk, then as soon as someone enters this chunk they get chunk banned, because the server won't be able to send them that many entities all at once.
What could be even more disastrous is if someone unloads and reloads chunks with these massive amounts of entities. Then the server would be at its knees trying too, and you'll end up with a very efficient lag machine.

would be great use for movecraft imo