Matter is a new protocol for smart things which means matter devices talk nicely to matter devices without the need for cloud services. No subscriptions. No payments.
If you use Apple home you just scan the code on the side and it pairs. Same for google. Your network needs a matter hub and these come in various ways but things like an Apple HomePod, Apple TV 4K and other google devices are matter hubs already.
I have a great experience with these https://amzn.eu/d/066ZEz2U
You can use their cloud app. Or as I have HomePods I just scan the code in Apple.
Matter can also be added to Home assistant in the same way. Scan/enter the code. All paired.
You can also then disable the devices internet access as it’s not needed. Your hub does all the work