Not sure why you think that guys who miss 10% or more of their tackles are "perfect fits" for the Pats defense that Vrabel and Williams are installing.
How would Vrabel be familiar with Joseph-Day? Joseph-Day's only year on the Titans was in 2024. Prior to 2024, he was with the Rams, Chargers and 49ers. Vrabel was with Cleveland in 2024 Vrabel would be more familiar with BJ Hill since the Browns played the Bengals twice last year.
Your claim that Joseph-Day would be a huge upgrade over Godchaux is based on what, exactly? Jospeh-Day is not and never has been a NT. Something that Godchaux is at 330lbs. Joseph-Day spent 319 of his 480 snaps playing DE. Your comparison is non-sensical at best.