I believe Coach Allen said it (at least) during a podcast posted on the premium side of “the other site.” Maybe other places too. Do you pay for Peegs site? Go wade through tedious hours of unedited podcast dribble to find it if its that important to ya. Podcasters have a false belief that 4 hours of babble is just what the world needs.
Or let me save ya some time and repeat the obvious - He didn't say “lack of in-game adjustments” was the only reason he decided to change OC, so dont seize on one coach-speak phrase, but he did mention lack of in-game adjustments as one of the concerns. Shocking, eh?
Almost as shocking as acknowledging that The most important, most responsible coach for an offense is the OC. And in 2021 our OC put up 17 points per game, after 29 in 2020. It isn't rocket science. The offense sucked, for pick-among-multiple reasons, including depth, scheme, play-calling, OL, WR routes, whatever. Gone. (Or keep him and let the Internet Football Illuminati complain you kept an OC who was “obviously” - to “anybody who pays arrention to football” - going the wrong direction.)
PS - Saying that a coach says in preseason that he loves his staff is meaningless, unless of course you can meet your own standard and link us to some coach saying he dislikes his staff in preseason. Which no coach said ever. It supports no meaningful idea. 98% of what coaches say in media is just pablum, not usable to make any point at all. The other 2% is when they want to send a message or make a mistake and let something meaningful slip.