The model you tried is one of the best available among the free ones. I see a 120b (not the 20b) free model also available when using the OpenRouter provider, can't remember if LM Studio has that one.
But IMO, unless you can find a way for the model to read the entire content, it won't provide accurate answers. For instance, my
RSS Reader plugin has an option to send the entire article. Works with some models.