Easily one of the worst UI's I've seen since 2020.
Timing the initial in/exhales is tricky, because the circle contracts, not to its center, but to a nearly invisible (on my screen at least) smaller circle in the middle. No visible counters.
After a while, it just says "Hold". No indication that we're done. And I sit there, almost dying for 2 minutes before realizing, that it's done some kind of quiet-quitting routine on me.
Other than that I enjoyed it.