Some Amazon devices (see a list here: https://www.amazon.com/b?ie=UTF8&node=37490568011 ) already support Matter devices, so you might already have everything that you need. The Tapo 110M (M for Matter) plug for example can easily be paired with them and work flawlessly (an also much faster than the non-Matter counterparts). And yes, they don't need internet access to work.

You still need the TP-Link app for some more advanced functions like power metering though.