I was thinking about this from Portland's view. Let's assume that Brad does offer Jaylen for Dame. This would mean that Brad didn't give Jaylen his supermax, because anyone signing a supermax can't be traded for a year. So he offers Jaylen with a year left on his contract to Portland for four years of Dame. Wouldn't Portland be concerned that they might be giving up their best ever (or second best ever, for those of us who remember Clyde the Glide) player for a one year rental who might leave for a more competitive team at the end of the season? If I was Cronin that would be weighing heavily on my mind, especially if Portland wasn't a team that Jaylen saw himself being in long term.
This is something I've brought up a couple times. Brown is very unlikely to sign an extension anywhere he's traded because of current extension rules (if i'm reading the new CBA correctly, maybe i'm not).
To illustrate: Brown's base salary is 28.5 million next year. The max base salary of an extension would be 140% of that final year number which would be 39.9 million. The starting salary off a cap of hypothetical cap of 145 million at the 30% max in free agency next year would be would be 43.5 million. So Brown can't really get to his max salary
guaranteed off an extension. That difference can be made up by bonuses which can also be carried over by up to 140% of the previous contract, but the net result is Brown can't even sign a fully guaranteed 30% max with a team he's traded to. The difference is even greater if the 24-25 cap comes in higher.
Brown is highly likely to just want to wait until free agency in 24' when he can sign a fresh contract clean of incentives. And at that point the difference in what his incumbent team and a new team can offer him over the first 4 years of a deal is only like 8 million or so. The only real advantage his incumbent team would have is a fifth year.
So a team expecting to be bad next year should, and will, be VERY wary of trading for Brown. He's a huge flight risk who probably won't extend ahead of time for financial reasons. Any team that trades for him probably has to be confident they are both good, and a place he wants to be. Otherwise they can't give uup the value Boston would need in a trade.