All dogs need is opposable paws.
I had some dogs a while back. I had a Lab-Golden mix who was a fetching genius, but I’m pretty sure he could distinguish about 3 dozen words, and of course he was sensitive to intonations. I used to try to experiment with toneless pronunciations of things like “walk” “outside” “cheese” and so forth. He knew.
Many people claim much wider vocabs for their dogs. I estimated that in a non-verbal way, he was about as smart as a toddler, obviously without the developmental potential.
Your experience is the same as mine. Like people, some are smarter. Intonation and words both give information.