OK, I get it. It's pretty different from the usual pattern of multiple save slots and manual saving (plus optional autosave slot). It's much closer to one-state-at-a-time, with a save slot to pick up where you left off. But normally games never get in a state where saving is impossible, which is what bothers me mainly.
Could I convince you to use one of these systems?:
1) One state, autosave
Autosave always enabled, there is a single restart/wipe save button with confirmation. (The simplest system. No need to mention saving at all except to say that it always happens at 8AM! Never surprising, but replaying destroys progress.)
2) Two states, autosave
At all times, the player is either playing Save A (red) or Save B (blue). Autosave always enabled. There's a button to switch saves, and a button to restart the current save (with confirmation). There's also a display summarizing the progress of the two saves, highlighting the one the player is on. It's possible to replay while preserving progress by switching slots, then restarting. (A flexible and clear system, but maybe over-engineered for a game like this.)
3) One state, manual save plus optional autosave
There's a button to en/disable autosave, a manual save button, and a restart button with confirmation. If the player never disables autosave, it's just like option 1 except you can save mid-day. But by disabling autosave and restarting, the player can play the early game while preserving their late-game save, and they have the option of manually saving the new run if they decide they like it. Doing so would replace the old run with the current run, so it should have a confirmation prompt. (Not my favorite, but I'd prefer it to the current system.)