@orangebucket already gave you some great answers, but just a few quick points:
- some momentary devices do work in the new app, but they need a few changes and so the ones you had in classic probably won’t migrate.
You can either track down @orangebucket ‘s Instructions in other threads for how to make those changes or you can just use a simulated switch and use the power allowance feature of smart lighting to have it always turn itself off after one minute. That makes it the equivalent of a momentary switch without the current issues.
- The new Alexa skill has a couple of major glitches. First, sensors are not consistently triggering Alexa routines for some customers. This applies to both physical and virtual devices and it’s extremely annoying. Engineering is aware of it and is working on it, but no timeline for a fix. There’s nothing you as a customer can do about it, so don’t even start down that rabbit hole. There are three or four threads on this, but official updates are being posted in the following:
Child devices also don’t work right.
There are other issues as well, just read the thread at the link and you can see those.
- The author of echo speaks is working on a new “light“ version. I don’t know if that will address your specific use case or not. Discussion near the end of the author thread:
https://community.smartthings.com/t/release-echo-speaks-v3-actions/173073/
- scenes and Webcore. See the new community FAQ