Change or fudge enough rules and you’re basically playing a different game.

No time constraints? Now the GM has less levers to pull on to make choices feel meaningful.

Not tracking rations? Then there’s nothing stopping the players from travelling back to town to rest after every encounter.

Lots of game rules feel “less fun” in the moment but the alternative is constantly playing rocket tag because now fights don’t feel consequential unless player death is on the line - and that’s an easy line to accidentally cross. And then you end up fudging rolls to balance encounters.

But you wouldn’t need to make individual encounters so hard in the first place if pc death isn’t the only negative consequence on the table.