See more discussion of the puzzles from the United States’ 2021 Puzzle Grand Prix on this post. Note there are some construction details and potential spoilers on that post so view it after you solve.
or solve online (using our beta test of Penpa-Edit tools)
Author/Opus: This is the 407th puzzle from Thomas Snyder, aka Dr. Sudoku.
Difficulty: 3 stars (estimate based off competition points; timing standards not available from our usual testers)