I used this CAN lib, works in Basic CAN mode with SN65HVD230.

Even more due to the pin mux of the ESP32, you can also use different pins, e.g.

#define CAN_SPEED CAN_SPEED_250KBPS
#define CAN_TX GPIO_NUM_17 // TXD2
#define CAN_RX GPIO_NUM_16 // RXD2

Because I used TXD2 and RXD2, I'm currently considering to check also the RS232 MAX based TTL converter and in case it works, maybe I will put only a 4 or 6 pin grove connector into the M5Stack proto board with housing and place the tranceiver into an external plug: one connector would then allow either CAN or Serial :-)

High Speed CAN transceiver can be used by custom design, I checked it based on my proto board:
http://forum.m5stack.com/topic/59/diy-mini-proto-board

Please post the line of code where you are creating the connection to the broker.

Is the broker properly configured in respect to port usage (e.g. 1883 for no encryption/no authorization)?

Yes, pretty close to your design.

No. There is the button module completely replaced. I would like to keep it attached. I thinking about some kind of encloser around the housing of the M5Stack with a slide in mechanism. That was also the reason way I was asking in this thread for STL model of the hole case.

My idea for a housing of the proto board would be more like a case that can pick up the complete M5Stack inclusive the button board without disassembling it at all.

It's a standard 7x5 cm board with interconnected holes. The mini bread board on it measures ~ 4.5 x3.5 cm.

@Kryten Thank you, this looks already good.

Better would be the housing of the base board because I need to align the pin break out area with the stands of the proto board. But it's a beginning.

Maybe also in your case also this workaround helps during using VMware.

Yes, but currently only the housing 3D model for the proto board is available on github. So it would be helpful to make also the core and base as STL available there. My idea is to create a "housing" which would allow to fix the core incl. base plus this extension in/on it.