I doubt I'm covering any new ground here, but I'm not too worried about the RBs, WRs, TEs, special teams or even the OL. May not always be pretty or flashy, but I expect that these units will get the job done. However, that still leaves two BIG question marks.
(1) Mac Jones. It's a QB driven league. If he takes a step forward performance wise, 10 wins should be the baseline, unless the defense is non-functional (more on this below). He doesn't have to be Tom Brady 2.0, but I would happily sign up for "2021 regular season Joe Burrow." That said, if Mac gets injured, or doesn't improve on last year's play, then I agree with posters above predicting 7 wins or fewer.
(2) The Defense. I have no idea what to expect here. Bill has forgotten more about coaching defense than I will ever know. But whether due to injury, age or scheme, they were non-competitive at times down the stretch last year. They should field a faster defense this year, and have a handful of young players that could end up being solid contributors (Josh Uche, any Jones not named "Jon" or "Mac," etc.) but are essentially untested. Even if the best case scenario plays out, Mac Jones is probably going to have to win some shoot outs.
Long and short, put me down for 10-7. Mac Jones builds on last year, and the defense (eventually) figures out how to get a stop or two when it counts.