Looking great! I especially like the shots with those red berries! (what are they by the way? :) )
If you want to get rid of those "patterns" produced by DOF, you can change random sampler to something else than the default one. See screenshots below for an example.
Update: I was just informed that the default sampler should be much more efficient in the long run, so changing it could be useful only if you want to render just a few passes. Generally the solution is to render more passes (lower GIvsAA value:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000516203). Denoising could be useful here as well, although the patters would probably be still visible.