Circles position
I prefer (personally) notification circles on the right, I think it is worth trying out circles on the left first to see how people feel, maybe it will be natural and we all will like it.
Nav on top vs side
I far prefer nav on side, it is way easier to use and click. Plus huge room constraints.
Nav highlight
With the nav, I prefer to keep the “big blue highlight box” vs shrinking it like it is now, there is some weird psychology at play for me with the tiny nav boxes. It feels really hard to click, despite no mechanics changing.
My brain is oddly saying, got to hit the tiny tiny box to change nav.
My thinking is that when stuff is less visually busy, there is a bit more room for larger avatars. That said, I think the current size you have is OK.
Anyway feel free to scratch that feedback for now.