That's about what we've seen as well (even directly from deepseek themselves).
We've been using it for async "heartbeat" processing and sms replies, but it's just too slow for live chat replies (which is a shame, as I'd really love to use it there).
Very capable model, but also very slow.
have you tried their flash model? pro was too slow for me too but I've found flash to be more than capable and it's faster than Gpt-5.5 at medium.