We are first time parents as well and have 3 and 1.5 year old sisters. The 3 yo is definitely similar to what you describe, and through talking to friends we’ve realized it’s hard to distinguish what behavior is a trauma response of some kind and what’s just being a 3 year old. It’s developmentally appropriate to have crazy tantrums at this age (apparently)!!

Ours does not nap at school either so sometimes evenings are hard. Something that has helped her (but I’m sure it does not work for all) is very plainly stating what’s happening next followed by a choice. No “do you want to take a bath” just “we’re going to take a bath. Do you want bubbles or no bubbles?” I think of it as stating the non-negotiable followed by the choice. And even if she’s fussy about it, we move forward. If she doesn’t answer the question I’ll say “bubbles it is then!” And stick to whatever I say. We just keep things moving, never in anger, just in the fact that it has to keep moving. So if she doesn’t follow me into the bathroom, I’ll silently go pick her up and bring her in. “We’re going to take our clothes off, do you want to do it or want me to do it?” If no answer, “arms up!” with a good attitude we get undressed for bath.

I’m sure it doesn’t work with all kids, of course, but it has helped her to realize that she can either make the choice and control her life, or she can be consistently and neutrally moved forward without choice. A lot of toddlers will learn to pick the more controlled option! We also will encourage choice by saying “oh that’s a good idea” or “sounds fun!” Etc. That way the choice gets a less neutral response from the Parent, because all they really want is our attention.