Because most big franchises are owned by large corporations, they’re almost inevitably going to fall into the hands of someone who has a different take on that universe sooner or later. Unless there is a strong guardianship over time, there will likely come a point where the legacy that came before isn’t respected, perhaps because it isn’t understood or simply because the stakeholders think a particular direction will make more money.
I don’t follow Star Trek or Doctor Who, but in the case of Star Wars, while I agree the sequel trilogy was problematic, I enjoyed the first season of The Mandalorian. So I think there’s still space to enjoy particular parts of franchises as big as these, even if the overall story or continuity is broken. And continuity, while important, isn’t everything. The KOTOR games are still highly valued even though they’re not canon.
My advice is that you look for some new franchises to get invested in, that aren’t built on decades of expectations. For sci-fi video game stories, I recommend Horizon: Zero Dawn and The Last of Us if you haven’t played them (completely different from these). In terms of shows, I haven’t been following any new shows in a while, but in terms of sci-fi I really enjoyed the 2004 Battlestar Galactica (a complete four season story) and Firefly (a complete one season story). I’m sure there’s more noteworthy stuff out there, if you subscribe to Netflix, for example, there are a lot of new sci-fi shows that people are talking about such as Altered Carbon.