3yr old waking up at night??

I’m not sure if this is the right group to post. My almost 3yr old has been fighting his day nap and is waking up in the middle of the night crying and not wanting to go to sleep. We’ve tried earlier bedtime and downtime, we’ve also cut down his day nap and letting him play Independently. It is definitely not teething. Definitely no big changes.

Idk what to do anymore. I’m getting frustrated since I have a 6 month old trying to sleep too.

Any ideas? Has anybody had the same experience? A phase maybe?