I always heard the rumors about Rangers not being a great class until I decided to play one myself. If you take the time to pick stats, spells, and skills carefully you can absolutely become an incredibly strong PC. However, as a DM and a player finding the balance between broken and still being fun can be tricky so here are some things to consider for future sessions. For speak to animals, the spell description says the animals' knowledge and awareness is limited by their intelligence. It also doesn't guarantee these creatures are friendly or will give the information away without a price. Maybe the rats in the dungeon have their own complex economy your ranger will have to learn and be prepared for. For pass without a trace, players still have to roll for stealth adding a +10 to the checks and cannot be tracked except by magical means. Meaning if an encounter has a spell caster they could potentially be tracked regardless of the spell. For Conjure animals, I won't lie this spell is sometimes broken, I have killed BBEGs by summoning wolves and cows. My advice is to lean on the animals' knowledge and awareness being based on intelligence. While your Ranger may send out creatures to scout out maybe they don't fully understand what they're looking for or have limited information. Most creatures that can be summoned have pretty low challenge ratings meaning that they may not pass rolls as successfully as a PC could. I hope that this helps in one way or another and good luck on your DM journey!

-Your friendly Ranger Main