Nice find!
Also remarkable about J0613+52 is the fact that it appears to be turning just like a normal spiral galaxy would.
That seems to agree with new ideas on galaxy formation triggered by the observation of early spirals and even bars ["Ripples in the oldest known spiral galaxy may shed light on the origins of our Milky Way", Space, By Samantha Mathewson published January 03, 2024; “Detecting a disc bending wave in a barred-spiral galaxy at redshift 4.4.”, Tsukui et al., Monthly Notices of the Royal Astronomical Society, Volume 527, Issue 3, January 2024]. The paper has notes on potential gas disks.
“The dominant gas disc, by itself gravitationally unstable, potentially leads to the formation of a gas bar (Barnes & Tohline 2001), as an axisymmetric 100 per cent gas disc is theoretically proven to form a self-gravitating stable gaseous bar structure (Cazes & Tohline 2000).”
The latter reference discuss gravitational convective and vorticity models and find the early spiral observed bending mode, with the convective “polytrope n=3/2” model recognizable as models for stars, star cores and gas planets [“Polytrope”, Wikipedia]. The “polytropic process” is a process of systems with energy transfers such as gas convection, so a stable dark and baryon matter gas only galaxy, and its rotation, seems eminently possible!