> what level is this compared to other Western paid version?
IMHO this is a difficult question to answer. Part of the power of paid models comes from the software supporting it. With local models, you have tons of workflows that can severely influence the quality of the result.
In my personal experience, the SOTA models are way more consistent and can handle more complex questions. Part of that is (probably) because I don't let my local model access the internet, while paid models do use the internet to look at docs etc.
You absolutely need to let models access the Internet if you want consistently good results. Pretty much any non-trivial task requires the model to do things like look up APIs, code examples, or existing discussions of a given topic.
You don't really need the Internet. Tons of documentation is available for download (either as a zip, or with the documentation site as its own git repo). Wikipedia is available for download. You can get reddit dumps, HN dumps, stack exchange dumps, etc. This can all easily fit on one hard drive.
Reading the actual code is also always a better source of truth than docs anyway (this is true for people and LLMs). Just clone whatever libraries you use.