On Bedrock servers, the gamemode and difficulty are set in Startup, not in Properties. Startup overwrites Properties every time your server starts.
Change gamemode and difficulty
- Open Startup in the menu on the left.
- Under Gamemode, choose the mode new players start in: survival, creative or adventure.
- Under Difficulty, choose peaceful, easy, normal or hard. Your changes save straight away.
- Restart your server, so the new settings are used.
Put everyone in the new gamemode
Players who have already joined keep their own gamemode. To put everyone in the new gamemode, switch on force-gamemode in Properties.