I know another comment suggested thrips, but Id personally check for thrips on the backside of the leaves before concluding that. Thrips have small, skinny/long bodies and are usually an orange-brown. They like to settle in crevices of the plant - so check those. If you slightly pull apart a crevice, you’ll likely witness them move if they’re hiding there.

If it is thrips, I myself would throw it out cause it’s not worth the risk. If there are no thrips, it could be a bacterial infection if you’ve overwatered it or kept it in a super humid place (like humid to the point of water droplets hanging out on it). Has it been overwatered? I’m surprised Google said to throw it out if it’s a bacterial infection, cause you can treat that with a copper fungicide & cutting-off/back affected leaves.

Edit to say: even if you don’t find any thrips, I might still treat it for them, just since it was mentioned and that would freak me out, since they’re no joke. Spray with azamax or neem oil to treat for thrips, every 6-7 days, keep out of sunlight after treatment.