The latest BDS update 1.19.51.02 have removed the option to edit game settings as operator in settings - game.  

Before we could go into settings, game, and here we could enable cheats, change between creative and survival, enable coordinates and everything else. 
Now this have to be done via terminal, or actually copy the bds world to minecraft windows 10 or android, just to actually do these settings. 

To replicate

Setup BDS 1.19.50.02

Make a new world or copy a existing

Make sure your user / account is set as operator

Now we can change things like difficulty, enable disable cheats, coordinates and such directly in the game menu.

Now upgrade to BDS 1.19.51.01

Move over world, server.properties, allowlist.json and permissions.json

World startup without any issues, all the same settings as last time on 1.19.50.02, but everything in settings - game is now not accessible, so cant change things in the fly, this is not good for my niece and nephew that change these settings on the fly when they play.

Client XBOX ONE and SERIES 1.19.51 on lan

Something must have happened when BDS got upgraded, i reverted back to older config file and now everything works as it should, never experienced this before with BDS, and I have used it since the first alpha.