Q.Spacing for emerald green arborvitae
I planted a hedgerow of Emerald Green arborvitae 3 years ago. I wanted a privacy screen with no visible gaps. The planting card stated to space them 24″ – 36″ apart. Wanting privacy, I decided to opt for planting them 24″ apart.
Today, they are filling in well. I am concerned that I spaced them too close together for their health and competition of roots, etc. Do the branches die back if they are touching? The only option I see is to remove every other one to provide more spacing. This would create 4′ of space between each one. Of course, then I have to figure out what to do with 13 or so trees! Should I do this or are the trees alright to remain 24″ apart permanently? Thank you!

Your planting at 2 foot spacing should be correct for the growing recommendations of Emerald Arborvitae border planting.
This is adequate for root growth and with proper pruning will yield you a good privacy screen.
Emerald Arborvitae can grow 10 to 15 feet height and will be about 2 feet depth when mature.
I would not remove any plants.
https://www.gardeningknowhow.com/ornamental/trees/arborvitae/growing-arborvitae-trees.htm