How long until Octopath Traveler 2 saves?

I played the game on my Steam Deck on a long train ride for the first time. It was mostly talking to people and cutscenes. After about thirty minutes I had to get off, so I closed the game. I realized I never got to manually save, so I tried to continue the game after and the option was grayed out. I’d rather not have to redo all of that again, especially if it won’t save again. How long do I have to make sure I can play so I can ensure a save occurs? Is this game a bad game to play in short sessions?

Also, is OC2 the tag for Octopath Traveler 2? I couldn’t find an OT2 tag.