The standards objective is to make common ground for IOT´s from different manufacturers. Thus making it possible to mix IOT´s from all the participants of the standard in ONE app.
Tuya has been member for some time of the CSA, which is the group that oversees the work on this important standard.
The work has been delayed again and again by adding new feautures and uses, mainly by new capabilities of hardware and chipsets, that was not foreseen from the beginning, as well as new platforms for the apps, Android, IOS, Windows, Linux, and Tizen.
The date for the release of v 1.0 of the standard and its SDK´s is now second half of 2022.
Meanwhile Tuya is the defacto-standard just by its enormous precense in products of today.
Wheater Tuyas products will be upgraded to the Matter-standard in the future OR the Tuya specifics will live on in paralel to the Matter- standard in the older Tuya-product is written in the stars.
You can read further on this here.