FYI, I think I successfully reverse-engineered the buyout. As we already knew, there is a retention bonus of $700k if he's employed on June 30, 2027 or fired without cause. According to USA Today, his buyout on 4/1/2022 was $1,881,250 and his buyout on 4/1/2024 was $1,431,250. That difference is exactly $450k, or $18,750 per month. If you keep subtracting $18,750/month, his 7/1/2027 buyout is exactly $700k, his retention bonus.
So at $18,750/month, his current retention bonus is exactly $1M ($700k retention, plus $18750 * 16 months = $300k buyout of final season).