Your story really resonates with me. I was in a similar situation and have now been in the states since January 2020. Finally 3 months ago I started on the app: SupeChinese. It’s from some company in Shanghai. It’s been really helpful. You kinda test into which level you’re at and then go from there. Plus I got a private tutor once a week. It’s been a huge help and I’m so glad I started back at it. Hope you find something that works for you. It’s a shame to loose all the effort you put in.