Wikipedia has a history of how lead was known to cause problems, dating back to antiquity. Some excerpts:

> Dioscorides, a Greek physician who lived in the 1st century AD, wrote that lead makes the mind "give way".[121][274]

> Lead poisoning from rum was also noted in Boston.[291] Benjamin Franklin suspected lead to be a risk in 1786

> The first legislation in the UK to limit pottery workers' exposure to lead was included in the Factories Act Extension Act in 1864, with further introduced in 1899. William James Furnival (1853–1928), research ceramist of City & Guilds London Institute, appeared before Parliament in 1901 and presented a decade's evidence to convince the nation's leaders to remove lead completely from the British ceramic industry.

I don't know much about forever chemicals. Is there the same level of evidence as we had for lead?

> I don't know much about forever chemicals. Is there the same level of evidence as we had for lead?

No. We have observational data in humans (which is problematic for drawing conclusions, since PFAS contamination tends to correlate with industry and population), and animal models, mostly in non-mammalian species.

As you correctly note, lead was known to be toxic since long before leaded gasoline -- the "question" was more about the delivery mechanism (auto exhaust) than the toxicity of the element itself.