If you did not change the context length, it is certain that it is not 2k or so. In "/show info" there is a field "context length" which is about the model in general, while "num_ctx" under "parameters" is the context length for the specific chat.

I use modelfiles because I only use ollama because it has easy integration with other stuff eg with zed, so this way I can easily choose models with a set context size directly.

Here nothing fancy, just

    FROM qwq
    PARAMETER num_ctx 100000

You save this somewhere as a text file, you run

    ollama create qwq-100k -f path/to/that/modelfile

and you now have "qwq-100k" in your list of models.