I found the OpenMQTTGateway project and got really interested since it can open up for a lot of interesting integrations to Home Assistant. I bought a LilyGo to start experimenting and could get it to read 433Mhz devices like Nexa. All this is possible due to the RTL_433_ESP library.
I wanted also to be able to write to the devices since I have several power plugs that use Nexa. That is not possible with just the LilyGo and the radio module on it. With the STX882 it should be possible to transmit. So I bought both a STX882 and a SRX882. This page describes how to connect these to a ESP32 or NodeMCU.
Have not yet tried to make the full setup and connect everything. Will update this post once I have tried that.