All signs right now point to Notre Dame for Diggs's signature later today.
Regardless of eligibility, Williams could leave for the NFL after this year. If he had back to back 1,000+ yard seasons and improves his receiving this year, there won't be much he could do in 2022 to improve his stock more. He's already a hell of a blocker. It's wise for RBs to leave early before there's a lot of tread on their tires too so no one should begrudge him if he were to leave early. Notre Dame has to prepare for that possilbity.
Love Estime as a prospect, but adding another back is important. Even with him, there are only 4 RBs on the 2021 roster at the moment - depending on how Kendal Abdur Rahman is counted.
In the end, LSU made a big push for him so he isn't some throw-in recruit. Diggs is a legit prospect and a good addition to this class.