My understanding is that the core research team is between 100 and 200 people. I don't have a great source for that - a friend of a friend is on the team. By comparison, Open AI's Chief Research Officer said their core research team was about 500 at the end of 2025[1]. With so few people, DeepSeek would have be more selective.
They are not playing pissing fest. They have revolutionary research on Vision if you read their white papers, they just take their time. Every major release from them has brought something really new to the field, V3, R1, OCR, V3.2, V4.
----
[1] https://youtu.be/ZeyHBM2Y5_4?t=483