While it's true you can't have multiple MicroPython interpreters running concurrently (or at least not easily; it's not that the design makes this impossible, it's just that all in all MicroPython is fairly young and development focus has been put elsewhere), it is possible to embed MicroPython. Not completely out of the box, needs some glue code etc. See for example https://github.com/micropython/micropython/tree/master/ports....