I finally spent some quality time practicing the serve. Playing around with my serve stance- which has been platform since I started playing tennis- I discovered the pinpoint solved 80% of my issues! I found that with a pinpoint stance, bringing up the rear leg forces me to transfer weight forward, whereas with the platform, I could sometimes keep the weight back, especially under pressure. The forward momentum also made the toss go a bit more forward naturally.
You can see the difference quite clearly on the slow motion videos:
Side by side:
I was surprised the change wasn't too difficult. Tried it in a practice set, was hitting it pretty well. I just forgot to bring the back leg up once