Our eyes also have the ability to desensitize to higher levels of light input, so the sun at high noon will be really bright but it’s the same as if you were in the complete dark for an hour and walked out into a brightly lit room. The eye gets used to the bright light. The same thing happens walking inside a low-light house from a bright day, it will take a minute to adjust but once you do your eyes have a completely different perception of light intensity.

With the solar eclipse, even 1% of the sun showing still lights an area greater than indoor lighting or perhaps even outdoor lighting, so we perceive it as still somewhat bright. This is sunset-level sunlight but the source is above instead of behind the horizon.