There is a current limitation in the available functionality for the tuya app controlled lights within the smart life app (which will talk to IFTTT and Stringify)
IFTTT works with the smart life app which is the tuya app equivalent. It also works the jinvoo smart plugs. If I were you, I'd move everything out of tuya/jinvoo and put it into smart life. There's no easy crosswalk and if you add more devices or want the interoperability later, you have to add each device individually (I've now done this 3 times because I'm stupid). It looks like smart life is going to be the main app for interoperability. Similar to magic home and flux wifi.
Anywho, in the smartlife/tuya app, only my jinvoo plugs have 'added functionality' built into the app. Those are the only devices that mesh well in IFTTT (I can run flows between smartlife/stringify/IFTTT). It appears that smart life acquired several new API relationships and while most of them have migrated basic functionality, it seems like they are having to go back and add the more advanced features to those that either didn't have it or didn't have a good crosswalk.
I know it's not the answer you were hoping for but I hope I saved you time, research, and hair pulling out.