Yes, it can be reduced if you turn everything off. Security monitoring. With the Tesla, you can turn off mobile access. and a few other things. I don't know about the other manufacturers. I guess they don't offer the continued security recording or other things maybe? Active features use energy. Shut off all the features, or don't offer them to begin with, and you'll reduce draw from the battery. I know on the Tesla and even my prior Chevy Volt, the car would do some battery conditioning on its own as I could hear it doing something, despite not being used. So OK, I guess it's normal on some cars that offer more access and/or security features and such. The Tesla is active at most times. Being that Rivian is mostly a knock off of Tesla's UI, assuming it will be similar.
I get annoyed by the Tesla fanboi's and have certainly done my fair share of criticizing of their ways. But, also have to respect that we have the EV's we have today because of them. A lone company took it upon themselves to prove that EV's could be appealing and practical. And they, by far, out sell every other EV on the planet. So, as much as they annoy me with a lot of what they do, they really don't care who's annoyed because people keep buying them. Rivian has already followed in many of their footsteps.