There is no
direct evidence of specific amounts of temperature rise that can somehow magically be attributed to human activities (e.g., we are able to measure all energy values of every single thing on earth and then determine what causes what exactly, etc.). Nobody even claims that this is the case; certainly not the IPCC.
The conclusion (temperature-changing effects of human activities) is derived specifically from taking the local maxima of warming we’ve seen in this very short window, subtracting the known non-human factors (of which the sun is one... hence the importance of the missing data), and then attributing the rest to human activities.
In other words, your statements, pertaining how we can deduce that their conclusions are correct, save for A or B (above), are the most quintessential example of “begging the question”.
Another important bit that I didn’t even mention in my original comment is that, not only does looking at TSI ignore other particle forcing qualities of solar phenomenon, such as flares and sunspots, But it also ignores the fact that, during such events, solar irradiance is measurably decreased. This means that the assumed human factor needed to justify the perceived temperature increase in the models is actually raised in such cases. This means that when using the models to predict the temperature on the earth, the models will actually predict that human activities that cause warming increase during solar events.