What if anything removes Sharpie black marker from colored cotton tee

Try spraying it with cheap aerosol hairspray. Then wash by hand in cold water.

https://oureverydaylife.com/how-to-remove-sharpie-ink-from-clothing-12289673.html

Try alcohol. Let it soak for a while then then wash as usual.

try unscented Oxi-clean ....the scented is so overpowering it's sickening. Should be safe with colored tee.

scissors

lemon essential oil. then hand wash with some Dawn dish soap

I would try a product like Goof off before giving up on it.

Plain old household rubbing alcohol is an effective way to remove marker stains. Place the stain face down on top of a couple pieces of paper towel. Dip a cloth in rubbing alcohol and dab at the stain. You should see the ink transfer to the paper towels underneath the stain.

If you have no alcohol, you can use hand sanitizer. Rub it in with toothbrush then wash item.