Equity is closer to "equality of opportunity" than "equality of outcome". "Equality" is neither of those things because it doesn't correct for differences in opportunity and therefore obviously doesn't yield an equal outcome.
There are certainly many people advocating for explicit "equality of outcome" policies e.g. various quota systems that mandate granting unequal opportunities for otherwise equally suitable applicants in order to achieve an equitable outcome for various groups (e.g. gender, ethnicity, caste, etc) the applicants represent.
This is the problem in your definitions. Are you talking about equity of outcome at the individual or group level? You are mixing the two there.
No on is advocating equity of outcome at the individual level. People are using equity of outcome at a group level as a measure of equity of opportunity at the individual level because there is an assumption that when two large groups of people have similar opportunities they will have similar normally distributed results at the individual level. If you argue otherwise, you quickly start getting into areas of bigotry by saying that a certain group is not willing or capable to make the most of opportunity.
But there seems to be a "definition mismatch" about what "equality of opportunity" means - I'm talking about equality of opportunity and equal treatment for individuals as they are right now at any particular decision point; and this is substantially different from what's measured by, as you say, "equity of outcome at a group level as a measure of equity of opportunity at the individual level" because that essentially measures an "integral" of all lifetime opportunities for all these individuals.
The key difference is whether we consider that "equal opportunity" should include or exclude compensating of earlier unequal opportunities. In general we're talking about specific decisions or policies that unavoidably come after some unequal opportunities e.g. the socioeconomic status of the family you're born in, which correlates with almost every measure of success. I would define "equal opportunity" as a "background blind" system that looks at the relevant attributes of individuals despite of or because of whatever earlier life they had - but it's clear that equal opportunity right now won't result in equal outcomes at the group level, since those would be influenced (and probably dominated) by all the differences accumulated before that. And vice versa, if you're trying to compensate for that, then you might get an equality of outcomes for the groupo, but at this moment you would be granting unequal opportunities to these individuals, even if they actually accurately compensate for other, earlier unequal opportunities to the same specific individuals and not just the groups to which these people happen to belong.
You admit "equality of opportunity" isn't practical right now due to existing systemic biases. The people fighting for equity would probably say it isn't practical in any foreseeable future. Maybe some day we will correct for systemic biases against certain races or genders, but odds are there will always be some sort of inherent disadvantage for various people. Physical disabilities are one example. That is where equity comes into play. Forcing an employer to install a ramp for a an employee in a wheelchair isn't being "background blind". They are not being treated equally because extra attention and resources are being devoted to them in comparison to their coworkers. However this unequal treatment is just in order to provide them an equal opportunity to overcome a disadvantage their coworkers never experienced. They would not have "equality in opportunity" without an inequality in how they are treated.
Equality of outcome is undeniably evil.
I call it Harrison Bergeron:
https://archive.org/stream/HarrisonBergeron/Harrison%20Berge...