Jagged edges on a cube despite 8x anti-aliasing

Hello there! I was messing around a random project and everyt$$anonymous$$ng was working perfectly, when all of a sudden jagged edges appeared on all objects. I've been trying to resolve t$$anonymous$$s issue for the past two dails, only to no avail. I have tried changing various settings, when at last I've uninstalled unity and removed all projects. After re-installing it, however, the problem still persists.

One more t$$anonymous$$ng to note is that the cube is displayed properly in scene view, but with jagged edges in game view... why?

These are the camera properties:

More properties included in the comment, since no more than two attachments can be attached. Thank you for your time in advance.