Minecraft wiki entry for Hardcore_mode, associated text: Bow (20 EXP levels). Infinity is very helpful, but it is rare (10% chance). Power will also help.
Sword (30 EXP levels). The most useful enchantment is Sharpness. Fire Aspect is useless against most Nether mobs (except Piglins and Hoglins), but is very useful in the End because endermen become neutral while burning. ‌[Java Edition only]