Hi Melissa --
I definitely agree with your core point that there is more than one definition for racism.
I simply don't use the phrase "reverse racism." Using that term in the first place is playing right into the hands of the "racism-can-only-be-systemic" or "racism=privilege+power" crowd. If mistreatment, bigotry, or discrimination is occurring in a situation where it wouldn't have occurred BUT FOR the fact that the targeted person belongs to a certain racial group, it's racism.
I view racism through the lens of having THREE main subcategories (systemic, social, and cultural). I delve into this with more specificity in my recently-published piece, "How I Define Political Correctness."
https://medium.com/the-bad-influence/how-i-define-political-correctness-d430f16459b0
If you keep scrolling down, it's midway through the article where I address the three main subcategories of racism.