Btw, an offseason buyout isn't a great option, I think BMac would much rather use retention to move him if he clears waivers.
If he goes unclaimed and stays on the books to the offseason, next year they owe him 2m signing bonus plus 6 million in salary for an 8m outlay. No matter what, they owe him that 2m. If they bury him in Hershey, he'd count 6.65m against the cap the whole year.
If they traded him at full retention, they'd cover half his 24-25 salary, so they'd have a 5 million outlay (2m bonus plus 3m salary, as presumably he wouldn't be traded before the bonus is paid in the offseason), his cap hit with full retention would be 3.9 and he's off the books after 24-25.
If they bought him out, they'd need to pay his signing bonus, plus 4 million of his 6 million salary, so a 6 million outlay, his cap hit would be 3.8 next year and 2m in 25-26. Essentially, buying him out costs a million more, saves nothing in cap hit next year, and encumbers the cap by 2 million in 25-26.