I sympathize with your frustration. A 1% success rate is extremely discouraging.
Do you know what the success rate is for non-DEI candidates? I believe there is some bias in the hiring process including racism, sexism, ageism, etc. But I also think that companies are hiring less than 1% of applicants in general. From what I have seen, companies are very bad at identifying the best candidates. But if you are getting 100 resumes a month and you hire 2-4 people a year, it's a roll of the dice just selecting the 20 resumes out of 400 to invite for an interview.
All of that is to say: don't get too discouraged. A 1% success rate would be remarkable. If you can achieve a 0.5% success rate you can increase diversity by 400%.
Personally, I'm a fan of meritocracy. I wish the most qualified people were surviving the roll of the dice. But I think it would be ideal if the most qualified people included a lot of diversity. As it is, employers' best chance to hire qualified people is to rely on human networks to help somebody stand out in the sea of resumes. So the more people of diversity you can land, the better chance there is for future candidates. And the better qualified your diverse candidates are, the more voice they'll get in future hiring influence. So keep pushing highly qualified diverse candidates. And while you're at it, push highly qualified non-diverse candidates so you aren't just seen as a diversity advocate. People might take your diverse candidates more seriously if they are perceived less for their diversity and more for their excellence. If 80% of your recommendations are diverse and 50% seem to be very high-quality, the 10% that are very high-quality non-diverse will change the perception of the 40% very high-quality diverse candidates.