How do I make a falling_block that I can select blocks through?

I am trying to make a grass field, only that it isn't actual blocks for the grass or tall grass, but rather falling_blocks.

However, when I attempted to use Markers:1b for this purpose, it ignored the NBT tag and just summoned a normal falling_block, that I can't select blocks through.

What tag makes this possible?

Basically what I want is to break blocks through other entities.

If you don't mind the block being a little bit smaller, you can try this:

/summon armor_stand ~ ~ ~ {Invisible:1,Marker:1,NoGravity:1,ArmorItems:[{},{},{},{id:"sand",Count:1}]}

This will summon an invisible, hitbox-less, weightless armour stand with a sand block on its head.

If you need the block to be the same size, you'll need to use a resource pack that changes the model of any entity to be the size of a block and look like a block.

A funny method would be to summon an invisible, weightless giant with a sand block in its hand:

/summon giant ~ ~ ~ {NoGravity:1,ActiveEffects:[{Id:14,Amplifier:1,Duration:1000000,Ambient:1}],HandItems:[{id:"sand",Count:1}]}

The block is diagonal, but that could be fixed by putting the zombie into a diagonally placed minecart. But it will shake anyway and is way bigger than a normal block.