Negotiating contracts yes. Game planning, reviewing offense, etc... no.
This isn't an OLB that comes in and rushes the passer or a CB that is on an island to shutdown a WR. We are talking about a QB that is the lifeblood of the offense - the person that holds onto the football more than anyone one else on the team. All plays, positioning, audibles, etc... goes through him. If the QB isn't there, whatever the offense does is only about 50% effective because is isn't him barking the calls, doing the cadence, nor throwing the ball.
It also isn't just a couple practices. You realize there is a lot of film study and meetings that go on behind the scenes, right? In fact, I'd say the "behind the scenes" is probably more important than the practice field.
Packer 2022 season is exhibit 1 for a QB not on the same page as 80% of his WRs. It wouldn't have helped with Watson as he was injured. But it certainly would've helped Romeo, Watkins, and many of the other younger guys.
I didn't say a team couldn't reach the SB with a QB missing OTAs. I said it puts the team at a higher risk that I doubt they would even try it. Team unity is a HUGE aspect of winning the SB. We clearly didn't have it this year (and that goes way beyond the QB - but he was part of it).
I can't think of a single example of a starting QB traded after June 1. Do you have one?