Hi @gordo521 and welcome!
It not at all complicated to get a more modern version of RawTherapee.
More info here: https://rawtherapee.com/downloads
or simply use https://rawtherapee.com/blog/new-rawtherapee-5.4-appimage
(you will find the Appimage at the downloads page as well).
Have fun!
Claes in Lund, Sweden
PS: @Elle did you notice post #3, above? It is green!
[Gordon, don’t get alarmed, it was just an in-house joke…]