In the US, I think racism (against black people) is stronger than sexism because racism against black people was socially engineered.
Humans are innately tribalistic. Any difference can be used to signal that someone isn’t one of us and that someone is useless and irrelevant to our tribe at best, or a competitor and threat at worst.
And humans have an inherit misogynistic streak because women’s reproductive systems are more valuable than mens. So men collectively want to ‘domesticate’ women to make them dependent, afraid and brainwashed so men can control their minds and bodies, giving men control of their reproductive systems.
But anti-black racism runs deeper than other forms of racism. America used to be deeply racist against non-anglo saxon whites. If you were Irish, German, French, Polish, Italian, etc you got a lot of prejudice 100 years ago. now those groups get treated pretty well. Latinos are integrating and light skinned latinos and light skinned asians feel comfortable voting alongside white supremacists.
But in order to justify how evil slavery is, we had to create a cultural narrative that black people were designed by an unquestionable, infallible god to be inferior people who deserved to be enslaved. We had to strip them of their humanity to justify how evil slavery is. We never did this to the Irish for example, stripped them of all humanity so we can justify enslaving them.
Also when you mistreat someone, you have a deep seated terror they will fight back. Because society has mistreated black people for so long, there is a deep seated unconscious terror that black people will take revenge for everything that has been done to them.
Plus the ownership class have intentionally stoked anti-black racism to oppose any forms of social redistribution. The new deal was designed to exclude black Americans as much as possible. The reason the US doesn’t have universal health care is that in the 1940s, southern whites were afraid it would lead to integrated hospitals and free health care for undeserving black people. The concept of the black welfare queen in the inner city is a major reason we had welfare cutbacks. Any time the social safety net is expanded, there will be dog whistles about how ‘hard working white people’ will have to pay more in taxes to provide benefits to ‘those people’.
My point being that racism and misogyny are ingrained into humans sadly. But anti-black racism in the US isn’t just an expression of this. It has been culturally engineered for centuries, and as a result is much more ingrained than bigotry against other groups (latinos, asians, LGBT, Irish, Polish, Chinese, etc), and more ingrained than misogyny.
FWIW, second wave feminism was only a few generations ago. And now women earn 50-100% more tertiary degrees than men. Women make up 53% of voters in elections, while men are 47% of voters.