Unfortunately it is difficult to take good pictures of this type of glass...plus the small size allowed by the forum, makes it even worse to see details.
I tried with a couple more pictures, attached.
However you saw it right: there is no pontil mark at all: the "texture" of the bottom of the vase is very much alike the rest of its surface. The external perimeter of the base is slightly ground (machined), to make it flat.
I guess this indicates that the piece is mould blown ? There are also no signs of mould joints.
Loetz is also the first guess i would come up with, but without a matching reference, it is difficult to be certain.
If you manage to dig out more, let me know. In the meantime, thank you for taking the time to answer so far.
Andrea