Your TX/RX levels and SNR are all great, and those events in the event log are really non-events. "TLV-11..." and "MIMO Event..." are just informational about the conversation between the modem and the headend. The only thing I see there that means anything is the one T3 timeout and one over the course of several hours shouldn't be causing what you describe.
I haven't been able to locate your Cox account by your forum info, so if you email us at coxhelp@cox.com we can take a closer look.
A few quick questions though, first, what do all the lights on the modem do during these periods of disconnection, and second, you say this has persisted through multiple modems and routers, but has a different computer been tried?