Spam lightning causes immense lag

On my realm, my friends and I created a joke that whenever something stands on a bone block, they get struck with lightning until they die or get off the block. In 1.15.x, this was all well and good as all it was was just a random noise here and there etc, but now in 1.16 and 1.16.1, whenever anything causes the spam lighting, even for a short period of time, it causes immense lag to the point of the server crashing sometimes. The exact command we used is listed below.

/execute at @e if block ~ ~-1 ~ minecraft:bone_block run summon minecraft:lightning_bolt