Thanks for checking all of that, it helps a lot. Your settings are fine. I’ve since found other reports of Unity browser games on the same engine version losing saves after the browser is fully closed, even though saving works on my end. The way Unity hands saves to the browser is the likely weak spot, and it could be failing on your setup even though it works on mine.
So I’m updating the game to save more deliberately, it will write your progress straight to the browser’s storage itself instead of relying on Unity to do it. I might also add in manual save exports and imports as a backup, so you can keep a copy of your progress yourself.
The update will also carry over any progress the game already has saved, so nobody playing now will have to start again. A save that’s already been lost can’t be brought back, but from the update on, your progress will be saved properly. I’ll post a dev log when it’s live.