As a former highly competitive cis female athlete who absolutely hated losing, I 100 percent support it. Trans women are women and deserve the same opportunities to compete and thrive as any other woman would. I don't feel that their inclusion meaningfully denies hardworking, dedicated elite female athletes that opportunity, and here's why.
I'm imagining myself battling with a trans woman for the final all-American spot in a race, and she catches me at the line. I'd be upset, but I'd be upset if any woman caught me! Every athlete has a constellation of advantages and disadvantages, and they all add up on race day to yield a specific result. If a trans woman's slightly superior strength allowed her to outkick me, a cis woman who lifts more than me or who naturally carries more muscle mass might have done the same. Research has shown that especially after protracted estrogen treatment, trans women's athletic advantages are simply not that substantial– they're similar to any advantages cis women athletes might have over one another by virtue due to differences in training, injury proclivity, or build. You give it your all on race day, and let the chips fall where they may, given the various tailwinds and headwinds that are unique to each runner.
And here's something that's missing from most of the discussion of this issue on these boards– trans women, and especially trans women of color, are socially ostracized, discriminated against, and invalidated at every turn. They suffer disproportionately from mental health issues, face serious threats of transmisogynistic violence, and attempt/commit suicide at far higher rates than cis women. For them, acceptance, respect, and inclusion is a matter of life and death. In contrast, at the and of the day, a race is just a race.