Default redis.conf location: /opt/homebrew/etc/redis.conf

Lookup directory where redis dump file is created:

🐿  redis-cli
127.0.0.1:6379> config get dir
1) "dir"
2) "/opt/homebrew/var/db/redis"
127.0.0.1:6379>

So the default dump file is: /opt/homebrew/var/db/redis/dump.rdb