The genetic machinery for limb regeneration is highly conserved (see reptiles) and predates the appearance of lissamphibians. There's almost zero chance it's possible with endotherms.

This is the paper: https://www.science.org/doi/10.1126/sciadv.abj2164 and it clearly states they treated a frog (xenopus, a common model organism), which does not normally regenerate when it's an adult. The paper clearly states that they treated with a set of factors that they believe induced a developmental plan- implemented by the transcription of DNA, translation of RNA, and expression of proteins. The initial treatment was removed, and the effect continued.

Also there's nothing about ion channels in this- the factors they used must have been actively transported- they bind to protein receptors.

So from a high level they say they have figured out how to “speak” to cells in a sense and instruct them to start building certain structures. And they emphasize that they aren’t making any changes to the genome or manage any of the low level processes themselves.