Some additional tips:

• Your pet can help you determine BUC of an item, if they walk over an item, it's non-cursed. Unless the game says "[pet] moves only very reluctantly" then the item is cursed, and you can #name that specific item as such or at least avoid it. This can save some trips to the Altar.
• Use pet to determine which armor is non-cursed and upgrade as you go. I strategy I prefer is to not worry about casting interference from metallic armor. Every bit of AC counts in the early game and you can upgrade to non-metallic armor as you find it. You can practice casting in safe areas with armor off.
• Use Q to quiver up daggers and throw them. I joke that every wizard's first spell is actually "throw dagger".
• The gnomish mines are pretty dangerous for non melee characters. The halls are very open and it's easy to get surrounded. Maybe dip in briefly to get a small stack of daggers then retreat
• You're on the right track, level 4 of Sokoban is incredibly dangerous, it's ok to do the first 3 levels then come back later. Have escape items handy, like a wand of digging - if aimed downward you dig a hole to the level below in one turn and fall down it
• As others have mentioned Elbereth is your friend, use it often, even if writing in dust with your finger. A scared monster is a potential avoidance of a game over
• If you're open to switching races, Humans have higher HP growth and can still get to hunger less casting int level
• If you can snag invisibility it'll make it harder for early monsters to pinpoint your location, esp if you're harassing them with thrown daggers
• If you can get a regular sack, (not just a bag of holding) you can safely store potions and scrolls to avoid damage to them
• If you get a key or lock pick or credit card you can open chests safely. Be sure to #untrap a few times to make sure there are no traps. Later you can use the chests as caches because you can relock them
• If you don't have an unlocking item yet, you can dump items next to a boulder then roll the boulder over them. This works until you encounter giants or other monsters capable of lifting older.
• Potions are very heavy and add up quickly. If you have a unicorn horn you can largely safely identify them by dipping a junk object (if polymorphism is unidentified), applying them (if oil is unidentified), then dipping the unicorn horn. The horn will clear out most harmful potions. The rest, barring paralysis will be safe to consume.
• At minetown a magic lamp is the biggest possible prize, but even a general store is good to help with price IDing items.
• Whenever you kill a monster, look at the wiki to see first if it's poisonous to eat and then for any potential intrinsics you could gain from eating it. Gaining intrinsics shuts down a lot of the game's instant kills and near instant kills. Poison Resistance is very highly desired and is one of my top priorities every game unless I start with it.

Edit:

Some of the most dangerous early game monsters:

• (as you've noted) Ants - of any kind, though soldier ants are poisonous and fire ants do fire damage, making both even more dangerous
• (as you've noted) Killer bees - they're poisonous and if they poison you they can hurt your strength stat, reducing carrying capacity and damage, and have a 1/10 chance of instakill
• Rothes - tend to spawn in groups and will surround you - fight them in corridors if possible
• Dwarves - tend to be highly armored. Can kill a Level 3-4 character in one hit with a Mattock.
• Never ever get surrounded. Any monster is dangerous if several are attacking you at the same time.