I'm glad things are moving forward for you pal, and you're doing alright all things considered. I will say though that she really hasn't changed at all. This is who she really was all along, she just either hid it or you chose to ignore the red flags. We all do that at some point.
As for the dating apps, it's been about 8 years since I had to use them but if I remember correctly they're a piece of **** to do right. Keep your bio light and try to Foster questions (most won't read it anyway) and get yourself 3 or 4 good pictures, no selfies. One doing an activity, one with friends, and a decent pic of just you or two.
Even if you look like an absolute giga Chad it will be rare you get messaged first. For us blokes, it's a numbers game. Try to tailor your messages to something on their profile and not just hi, how are you? And remember to send messages to multiple different profiles each day.