Google's John Mueller said on Twitter that he believes using the nofollow link attribute for internal PageRank sculpting is a waste of time. He said "I think it's a waste of time to do that" when asked about it.
Here are those tweets:
If it doesn't work, don't use it :). In general, I think it's a waste of time to do that. In practice, people waste their time on it anyway.
— 🍌 John 🍌 (@JohnMu) October 25, 2019
I suspect many SEOs disagree with John on this but what else is new.
PageRank sculpting predates the nofollow attribute, I believe Bruce Clay use to call it siloing. In any event, Google has never been a fan of SEOs or webmasters putting time and effort into that.
Forum discussion at Twitter.