@Vixen I continue to use RawTherapee and GIMP as my editing tools. GIMP just this year was finally updated to 3.xx version that has been promised for years. Think of RawTherapee as the replacement for Lightroom and GIMP as replacement for Photoshop. Not all the tools are available, but all the important features are. No AI assists, and that is more a feature than a flaw to me. I think free for life is worth the awkward relearning process.
I have largely switched to DigiKam for importing and organizing files. Also free, open-source. It does just a bit more than Nikon's NX Studio and is not limited to importing from Nikon devices. DigiKam does sort of allow you to integrate a little with RawTherapee so you might launch it by selecting a Raw file in DigiKam, but I find that does not work well yet. But maybe someday.
I did try buying Luminar AI some years ago. It lasted about 6 months until it did an update stopped working on my PC entirely. When I investigated that, tech support informed me my CPU is too old and no longer supported with that update. So remember you need a pretty recent computer to use all that AI enhancement. I'm still trucking on with that obsolete CPU computer.