The thing is there are really only 4-5 teams that can give him even what would be the 30% max, and those teams are bad and/or young teams. MEM, ATL, CHA, CLE and maybe NYK. Are any of those teams going to be at a point where they want to sign a 30 year old max guy in the middle of their rebuild? And even if they do would Hayward want to go their and basically give up competing? I don't really think so.
That leads me too believe he's either opting into the final year and will try the market in 2021 where he will be 31 years old but a lot more teams will have cap space (everybody is opening space for what will be a more robust market). Or he'll opt out with an agreement from the C's to sign a longer term deal for probably less(per year) than the $34 million he'd make next year.