As the title says, i'm thinking about upgrading from a 1080 TI to something else, maybe a 2070 or a 2080TI, but I am not sure whether the upgrade is worth the cost or if it's really that much of an upgrade at all. Am I better off waiting for the next generation instead? at the moment i'm only using one 1080p monitor.
Not worth it no. Besides, 1080Ti is faster than the the 2070 in most games. All cards mentioned are a bit much for 1080p if refresh rate is 60Hz. The cpu needs to deliver frames to the gpu too so cpu also play an important role on higher refresh rates.