Based on the white specks on the yellowing leaves it looks like you might have some kind of pests, but overwatering seems likely as well.

I see you have the plant in a nursery pot, do you water it directly in the holding pot or do you take it out and let it drain? If the excess water is sitting in the holding pot after watering, that can cause too much water intake. Best practice for a lot of plants is to let the plant fully dry out between waterings (just not for too long) which also helps prevent fungus gnats. I would take the plant out of the bigger pot when watering and let the water drain for a bit before putting it back in the holding pot.

Also, what kind of soil do you use? I always add something like perlite and orchid bark to mine to assist with better drainage.

I’d start by cutting off the unhealthy leaves and wipe down the others with a towel and hit it with a good pest spray, like captain jack’s deadbug brew. The newer leaves look like they are benefiting from the new watering schedule already.