Maximum number of quiet moves in a position The question of how many captures a position can have has been asked in the past: Maximum number of captures in a position

Without captures, and without promotion, which I define as “quiet” moves, what is the maximum number of quiet moves that one side can have in a legal chess position can have?
The maximum number for one side in a legal position is 216 quiet moves, according to this 46 year old chess problem.

[Title "Thur Row, Chess Ultimates 1974, 216 Non-Capturing Moves"]
[FEN "R6R/1K3Q2/3Q4/1Q4Q1/4Q3/2Q4Q/Q4QNN/2BB3k w - - 0 1"]