Hi! I recently acquired an X170KM-G myself, and I'm also interested in installing a standard MXM GPU. Clevo's proprietary MXM cards are simply too expensive.
How has your research been progressing? Have you made any further progress?
Have you ever tried the standard industrial MXM RTX 3080 card from Aetina International? It has a separate power connector that needs to be adapted to a 9-pin connector. I think it could be a good candidate for testing whether the compatibility issue is related to the power supply.
However, we would first need to modify or make a custom power cable for it.
At this point, your forum thread seems to be the only detailed information I've been able to find worldwide about this particular compatibility issue with the X170KM-G.
I'd really appreciate it if you could share any further findings or progress. Thanks!