IANAST (I am not a speech therapist), but honestly, that doesn’t sound “behind” enough to warrant that significant an intervention.

Yes, animal sounds and names count from a cognitive development perspective.

Keep doing what you’re doing with loads of stories, talk to him a lot (put your phone away if you have a tendency to use it when he’s around), take him out of speech therapy and let him develop at his own pace. Spend the therapy money on books, a zoo membership and taking him to visit his grandparents if they’re around.

Play with words, play rhyming games, make words up, reward saying things out loud. Be kind and patient, like you would do instinctively anyway.

Ignore the people who make money from having your child in therapy recommending even more therapy.

Reassess in 6-12 months.