I am by no means a professional, just a hobbyist at best, but I've been tinkering with RawTherapee and have briefly used Darktable. I use those for single shots/touch-ups. I can't speak for any of the advanced functions, but they might be a good starting point. As for working with layers, maybe try GIMP. Cool thing is that they're free and cross-platform. Hope this helps.

Thanks for your help

Thank you for everyone who commented.

@sdsphotographer I would be using the camera for Portrait, Nature, and food. Thanks for your help.