The reference cited title, "The Way of Water: ALMA Resolves H2O Emission Lines in a Strongly Lensed Dusty Star-forming Galaxy at z ∼ 3.1",
https://iopscience.iop.org/article/10.3847/1538-4357/accd72
Good to know the z number used in this cosmology model interpretation. Using Ned Wright,
"The age at redshift z was 2.094 Gyr.
The light travel time was 11.628 Gyr.
The comoving radial distance, which goes into Hubble's law, is 6578.5 Mpc or 21.456 Gly."
The space.com reported, "The galaxy, J1135, is located 12 billion light-years away and is seen as it was less than 2 billion years after the Big Bang."
The comoving radial distance shows today it is more than 21 Gly from Earth and space expands some 1.5x c velocity for that distance.