A lot of the exposition comes down to reader-preference and ability to focus. Some people hate exposition or info dumps and want to get into the action, and others need the explanations in order to make sense of what's going on. Maybe casual readers who are just tuning in for a quick read during a busy commute will be less able to take in the new information. So I guess it's a matter of who's your target audience.
I only read chapter 1 Echoes of the Bear for now (might come back later though, it looked interesting). Honestly, that prologue sounds interesting, but there's maybe a bit too much going on - new names, new concepts, histories to remember. It's a bit overwhelming, especially since the names are pretty "foreign", making them maybe harder to remember. I wonder if this part scares off new readers? Could it be told less as a textbook and more like a fairytale or juicy gossip?
It gets easier at the start of the chapter proper, once you understand who Lena and Setsune are. The dialogue is easier to handle and there are job titles and such to help you understand their role in the world. Maybe a couple of details could be added to make the first scene clearer from the first sentence so that the reader can picture it in their mind easier. What or where is this stage? Theatre comes to mind first, but it seems to be a court. Is "The woman" in white kimono the samurai mentioned in the previous sentence, or Setsune, also mentioned in the previous sentence?
There are quite a few descriptions of what people and their clothes look like. This is good, but could there maybe also be similar descriptions of what the place looks like? For example, when they hit the button, where is this button, where did it even come from? Maybe what it looks like. If you first describe it in the text, you draw the reader's attention to it gently. The reader goes 'huh, that's odd, there's a button in my medieval Japan story'. Then you say that the characters hit the button and stuff happens. The reader can go 'oh, that kind of button, wow it's a scifi story'.