I think weekly lineups should lock as games start (similar to daily), rather than all at once with the first game of the scoring week. If daily lineups lock as games are played, I don’t understand why weekly lineups don’t follow the same protocol.
My reason for this belief is that MLB teams that don’t play on Monday generally hold off on making roster moves (IL placements, promotions/demotions, paternity/bereavement) until Tuesday morning. They have the ability to backdate IL stints, etc. as needed, Ottoneu players do not. This creates a situation where a player can be unexpectedly unavailable for some (if not all) of a scoring period after already being locked into the weekly lineup, resulting in the loss of significant (potentially league altering) production. This has happened to me multiple times this season already.
If players locked as games started, the opportunity to replace them exists up until all teams for the week have played their first game. I think this would be a significant QoL improvement that would increase league integrity as teams could avoid losing production due to unexpected player unavailability.