Ah, where to begin?

Saturday, Feb. 13th, I was doing doordash in my 2002 Limited. I got a few orders out and I was hyped because it was paying well due to the snow and how insanely cold it was out. I pulled up to a McDonalds and picked up the order, started the car, and it started running super rough and I started to smell coolant. Like, very strongly. I went outside to check it out and the thing was dumping white smoke out the exhaust. Keep in mind, the engine was definitely warm from the previous couple of hours of driving. I will mention, the 10-15 mins or so prior, I did notice the engine sputter a few times, and just during normal driving. I wasn't accelerating and it wasn't under crazy load or anything.
So that night, I arranged to have a tow truck take it to a local mechanic. The next morning, I decided to bring it back to my house because I figured a mechanic would charge me at least a couple grand for a HG job, since I thought that's what the problem was. So I got the car back to my house on the 14th, and the work began the following week. Fast forward just over two months. I've replaced the headgaskets, resurfaced the heads, replaced a few odds and ends, and finally gotten the motor back together. And now it won't start.

It won't start. It'll crank and sometimes it will sound like it's about to start and whatnot, but it won't. Occasionally I'll get a pop in the intake or the exhaust, which I've heard is a possible symptom of incorrect valve timing? So I checked and with the crank at the 0 mark (top dead center cylinder 1, right?) both cams line up. And yes, I do have both my intake and exhaust cams on both banks aligned with that little dot lining up on the teeth. Fun fact to note before I forget: I have the 3.4L V6. I also checked my spark plug wires and those are all in the correct places. Help.

ps sorry my writing is awful