Darktable is the only accurate LR Classic alternative. The other two only offer Develop capabilities.
You need to understand your requirements in post processing software and which tools should be considered. LR Classic has a serious image management database that is more special than the development capabilities. The latter, while powerful in LRC, can be matched more or less by RawTherapee and other image processing tools. LRC also offers a good, not great, printing capability, book making, a useful mapping, strong integration with Photoshop, and the full Adobe Creative Cloud bucket of apps, which can be highly valuable if you need a no-additional-cost web presence.