Summon falling_block with horizontal velocity and no air drag

I want to have falling block going horizontally at a constant velocity, but even with nogravity they slow down and eventually stop.

I tried to update their speed with a repeating command block constantly setting their motion, but it’s just too laggy.
Here’s how I spawn the falling blocks:

execute as @e[type=minecraft:armor_stand] run execute positioned as @s run summon falling_block ~ ~2 ~ {BlockState:{Name:"minecraft:gray_concrete"},Time:20b,Motion:[0.0d,0.0d,0.0d],NoGravity:1}

Here’s how I set their motion:

execute as @e[type=minecraft:falling_block] run data modify entity @s Motion set value [0.7d,0.0d,0.0d]