He is still playing at a fairly high level at 35. From 2018-20, he averaged about 600 yards and earned about $4.5M per year. Another three years too early is better than a year to late outcome for a team with the worst group of skill players in the NFL.
So before everyone calls out Amendola, let's remember this goes both ways. He took paycuts to remain in New England to win championships, play with Brady, and build a winning legacy, and the team then kicked him to the curb despite that he was still affordable and productive.
But I don't kow why he's negotating a contract by himself...get an agent.