Within reason, things were scaled. Bosses/monsters still had ceilings and floors on damage/hp/defenses. Being low level meant that you were fighting the weakest version of each boss most likely, but even the weak versions could hit harder than your max health at a minimum at certain level ranges.
The completely non-intuitive and annoying way to play the game "low level" would be to find the lowest level mobs you could that had spells, draw until you were full, then run from the battle. Junction your best shit to whatever stats you could and go for it. Most specifically, find npcs with the Life spell, draw until max on each character, and put GFs that had junction-hp on each character so you could double your health, letting you survive long enough to use attacks and cast other spells, and if you could get to a state of low health where you wouldn't die from a hit, exploit the fact that you could just skip turns until limits came up and pop those nonstop.
8 was goddamn terrible outside of the card game =|