Our best advice is to stick with your plan to at least reduce your daughter's dependence on electronic activities. Too much of any one activity usually is not a good thing, and it sounds like one of your biggest challenges will be to find "healthy" activities to fill all the time she used to spend on playing video games. She will need a lot of support from you in this area. She is not happy with this new arrangement and the nightmare you are experiencing is her way of letting you know that. But at this point, setting limits is truly the best thing you can do for your daughter, regardless of her age or diagnoses.
Above all, remain calm and don't let your emotions get in the way of your parenting. As you redirect your daughter to other activities, keep the conversation about video games extremely limited. She will continue to test your limits by trying to bully or shame you into giving in to her demands, but allowing her to go back to her video game habits will only create another kind of nightmare for your family.
As for alternative activities, try to structure her days over the next few weeks so she sets aside time for reading, being alone, playing outside, going on outings, playing with friends and spending time with you. If you can identify other activities she likes (especially things she had stopped doing in order to play video games), be sure to build them into your daily schedule so she can regain those experiences.
It's typical for children to push back when parents make changes the children don't like. Your daughter is doing that now, hoping you will change your mind and give in. Stay strong and determined. And remind her that even though you have set a 30-day, technology-free period, her behavior during that time will determine if and when she'll regain access to devices and how much she'll be able to use them. Make a list of behaviors you want to see from her and explain that those behaviors will show you if she is ready for some limited technology time.
Also, be consistent in monitoring her behaviors over the 30-day plan. So if you set behavioral expectations for your daughter and she throws tantrums for 28 days, but then meets your expectations for the last 2 days, she should not earn back her access to video games and technology. The goal here is to help your daughter become a socially well-rounded child. To accomplish that goal, you can teach and practice social skills like how to accept "No" for an answer and how to follow instructions with her each day.
Visit the website internetsafety101.org for more information about Internet safety and limiting and monitoring kids' access to technology.