The concept here is interesting and I thought it was worth playing through once to experience. I have a few points of feedback. For one item, please see my reply to an earlier comment about why phase IV started dragging and what I discovered fixed the issue.
Second, I might have played a second time to see another ending, but I wasn't able to. After I chose my ending and reward, I was given the intro and explanation just like at the beginning; I pressed the blue button again; and then I was put back in phase VII with everything completed, just how it was before I finished, but with no obvious way to trigger the ending again. That seems like a bug. The only difference was that the activities section said "all activities, already imprinted in the body." I chose the third ending, and I think I chose the second reward because it sounded like all the activities would be unlocked from the start?
Third, I played on mobile (Android - Chrome on a moto edge), and while it was playable, the layout was definitely a bit wonky. The narrative text temporarily floated over the log in the lower left corner so that the text was hard to read until the floating copy went away. But some text wasn't retained in the log, so I had to try to read most of it as it floated anyway because otherwise I could miss some bits. Also, the manual action button ("walk" etc) would only respond if I tapped the upper edge that extended beyond the border of the log area. Having the full button area to tap would have made playing more comfortable.
Finally, the journey of introspection and creation was interesting to read, but it wasn't actually very interactive beyond gathering enough insights to systematically collect all the items in each phase. Gathering the items didn't seem to do anything until I had all of them, so once I figured out how to get the higher level activities in phase IV, I boosted insight production and then just zoomed through the items all at once. It would be more interesting if the later phases had their own secondary currencies that get produced by the items in that phase, and maybe the items interlink so that some require insights and some require the secondary currency. You want the player to have to slow down and experience the items individually, not click through them all at once, but if it feels too slow, it's not going to be fun either, so it's a tricky balance.
Good luck, and thanks for sharing your game!