That basically cutting him, which they aren't offering. They are saying trade, which suggests you take the contract. Now they may eat some money, like what happened with Foles, but they aren't paying 30 million for you to take Ryan off their hands.
And it is going to cost draft capital. For a 35 year old QB, that statistically, was outperformed by Trubisky this year. Yes that will make people cringe, but Ryan had plenty of bad games this year. Not everybody gets to pull a Brady and play into their 40s.
When you trade someone, you don't get to move the cap hit from the signing bonus to the next team. Any money your team has already paid to the player stays on your teams salary cap. RYans contract has $18.6m of signing bonus left (spread out over the next 2 years) , and $19.8M of "restructure" AKA moving salary to signing bonus after signing to create cap space in 1 year over the next 3 years . These parts of the contract stay on ATLs cap no matter if they keep, trade, or cut Ryan.
The team that trades for Ryan only pays his base Salary, Roster Bonuses, Any "option" salary, and incentives. Ryans combined total for those are 2021 - $25M, 2022 - $27M, 2023 - $30M.
But you're right that the big question is going to be cost to acquire (i mentioned this in my post). It's probably not worth it to the Bears to give up multiple day 1/day 2 picks to get him. We also don't know what the 2021 cap will be, but its very likely Bears would need to clear cap to afford Ryan - that's another price to consider.