According to Lenovo's website, these are the maximum (interior) dimensions:

322 x 223 x 20 mm

Whereas the X1 Carbon (Gen7) also has the dimensions 323 x 217 x 15 mm according to the data sheet and fits in without any problems. One or two millimetres more in one direction should not be a problem, as the material is flexible. Just not in all directions at the same time :-)

Oder des L380

It has pretty much the exact dimensions of a Lenovo Carbon X1 5th Gen -> 14inch inside.