Can you change the settings that turn autosave on, and change autosave from end to beginning of day, and replace them with two options:
autosave at beginning of first player's turn
autosave at end of human player's turn
Both of which can be selected at once, or neither of them.
And the filenames would be:
"autosave_daystart.sav" for beginning of first player's day, and
"autosave_turnend.sav" for save at the end of the human player's turn (you would decide whether this means the latest human player to have their turn, or whether each human player would have their own end of turn autosave that would be replaced next turn of their's).
Any end of turn autosave would be saved before any action happens and would allow the human player to end the same turn again when loading.
Note, this means that you can choose to have one of the autosave types, or the other, both, or neither.