The size M could be bought here
Apple Natural Titanium Milanese Loop (Titanium, Apple Watch Ultra)
Unfortunately, the availability is currently not good and we do not have a delivery date.
You're right, this is the size L. I will forward the incorrect specification to the relevant department for revision, thank you very much for pointing this out!
The "Natural Titanium Milanese Loop" watch strap is available in different sizes, but the specific size you are looking for is "Large". It fits Apple Watch models with a size of 49 mm.