I’ll offer a few associated comments (I am not part of the NINA team).
Most of the apps you mentioned are … let’s call them venerable. They have a long history, a large-ish installed base, and a fairly slow development cycle (I’m sure some developers may disagree, but just maintaining backward compatibility with a large base forces a certain slowness on the processes, but even so some seem really lethargic as though the developers just lost energy).
NINA is developing fast, the nightly version with the advance sequencer changes rapidly, based on real use by both the developers and fairly real time feedback on discord (and elsewhere). Fast does not always equal better, but it does mean that NINA will incorporate new features or techniques more rapidly than you are likely to see them in its older cousins. This newness also means it may not have features that have been around for ages in other programs, that might not have been considered useful to these developers. Since it is not a commercial product they are not really trying to satisfy every SGP or TSX user’s likes, only their own (or what they think useful). Personally I think this is good, making just another SGP is rather pointless, just buy SGP (as an example).
Developing fast also means there is a certain onus on the user to keep up, especially if you are using the nightlies (which honestly most people may want, as the features are great). If you upgrade to clear some bugs, you will also find differences in the UI, or in how triggers work, from the last time you tried it. I’m coping with that now as I was without a mount for a couple months due to a repair. And frankly the documentation on changes is present, but not terribly easy to find and digest for a user. Some people love this fast changing environment, some will hate it. Only you know which camp you are in.
It also has a very different support paradigm. Most of us are used to forums for user-to-user support, or email/phone for vendors. Discord takes some getting used to. It works, but it is a bit of a paradigm change you need to come prepared to learn.