I agree.
When you have a large PR like this, here's how I like to get it reviewed.
1. Give reviewers sometime to become familiar with the PR. They might not understand all parts of it, but they should have at least a cursory understanding of the PR.
2. Have a meeting where the PR is explained in front of the group of reviewers. The reviewers will understand the PR better and they can ask questions in realtime.
3. Let folks review the PR after the meeting in case they spot anything else, or think of additional questions.
Most of the time PR review is done asynchronously, but doing most of the review in the meeting can also be a decent team building exercise.
Yeah, ideally the reviewers have been in standups with you so that it isn't all new as a concept to them to begin with, or there's generally been communication that you're going to land the plans for a nuclear reactor in their work queue.
Hopefully you've been going around and around at a high level communicating back all the problems that you've hit and the design issues that emerged during exploratory surgery.
Then, you definitely want to schedule at least one meeting to go over it. Which can become several meetings, including follow-up meetings with one or two individuals to pound out some specific issue. Depends on the complexity of the nuclear reactor.