So I would really like this episode in isolation, I think it has nice themes of moving on even if you've made mistakes and death valley was wonderful to see. It's just that as a continuation of episode 4 which touched on the colonial (and genocidal) origin(s) of the national parks, a continuation of those themes feels missing.
Like for example Yosemite getting over the trauma of forgetting we see her experience in episode 4 offscreen would be fine, if not for the fact that she's the only native charachter and so we miss that perspective, especially because episode 4 actually conveyed really well the existential dread and fear that (cultural) genocide brings, knowing that things were different once but still only being able to conceptualize yourself through the colonizers framework. I was really excited to see where you were gonna go with that but then it's just... dropped. It matters to the overall themes too, since even though "You may forget and die, but the now matters" is a nice message, in Yosemite's case this forgetting is because of a genocide which forced her current identity upon her.
And I get that maybe you feel that it's not your place to talk about the native experience but then you shouldn't have written a story where that's necessary. I hope that the next time you set a story in the USA we can get a foregrounding of native experiences or at least one that doesn't go "look at this cool bit of the US" without considering the material conditions that made it like that.