Mesh with smaller scale flickering/disappearing at far distance?

I think this is a problem with TemporalAntialiasing. You can test this by:

  1. adding a post process volume
  2. Set unbound to true
  3. Go to Misc->AA Method and set the dropdown the FXAA.
  4. See if that fixes it

Many effects rely on Temporal AA so be aware it could mess things up. The flickering will be more visible in editor/PIE versus standalone. Your final game will be played in Standalone so be sure to test there.

Also note that once you add surrounding features and maybe some depth of field these issues will not be so noticeable. Your current setup is a worst case scenario.