I am not aware of the wiring arrangement (often referred to as "pin out" by many) for the M1 end and could not find anything online that indicated that.
If you had the wiring arrangement it would be easy to have a suitable cable custom made, it i just two 3.5mm plugs and two wires. Technically it should be 75 ohms but I understand at such short lengths that is not important.
The Clarinet end would logically be the normal two pole despite that many cables use three pole, only two are used, I imagine they use three pole due to easy availability.
I did find this one on AliExpress, it mentions Shanling M2 and M5, I can't imagine that Shanling would change the wiring requirements for different players. It is very short which might not suit you, perhaps if you contacted that store they could make a longer one for you.
With a working cable in hand you could easily determine the wiring arrangement to have a cable made. Alternatively you could get in touch with Shanling to determine what the wiring arrangement is, perhaps ask on the M1 thread here.
Does the M1 come with a coaxial adapter by chance, that would let you assess the wiring arrangement.
https://www.aliexpress.com/i/32971398688.html
Sorry I don't have anything more definitive but I hope that helps.