I don’t understand how this is legal action?
Well just the use of the trademark would probably be enough to file a DMCA takedown. But beyond that modding the game entails using its modding tools, which have an EULA, which stipulates no paywalls for mods.
Technically the modder has legal recourse, they could argue fair use and file a counter-notice. Then CDPR would have to sue in front of a court. But given the financial and legal risks it seems unlikely a counter-notice will happen.
Honestly the only real chance is to come to some kind of agreement with CDPR, which they seemed to heavily telegraph is possible in their public message ("we never allow monetization of our IP without our direct permission and/or an agreement in place").