It's not just you. I tried an Opencode Go subscription, and experimented with most of their models (GLM, Kimi, Qwen, Deepseek), and none of them got anywhere close to Opus - the difference in quality was very noticeable, especially with Deepseek V4 Pro and Flash.

The only caveats: I didn't play around with Qwen 3.7 Max very much, and of course these models are far cheaper than Opus.

But any suggestion that Deepseek approaches Opus in terms of quality/intelligence immediately makes me suspect propaganda - it's that noticeable of a difference.