You can survive, but its a bit hidden:
If you bought Annie the Pendant of Destiny in the very beginning of the game, you survive without dying (during very first interaction with the item vendor in eternum)
However i don't think the level loss is a huge debuff: level in Eternum seems to be more a vanity thing or rather, it shows how powerful you are/were, but you don't gain power FROM level ups but levels from completing hard challenges. The real debuff for normal players is loss of equipment from dying, but eternum player skill rises from actual personal skill, not points distributed during lvl up like classic rpgs.