I will have a legally blind student in my Fall 2021 class and plan to use R/RStudio. She has taken two courses with me that required extensive use of Excel. Her assisted technology made it easy for her to use Excel. Is there any reason to believe that R/Rstudio would not be as accessible as Excel?
Generally speaking, the regular R GUI has been easier to use for blind/low-vision users (though RStudio has been working on accessibility features, e.g. the link from @williaml).
A. Jonathan R. Godfrey (who is blind, himself) has done quite a bit of analysis on R vs. other statistical software for blind users, and written the BrailleR package (as well as a book on using it), all of which might be helpful to you.
I should note, however, that Excel wasn't part of the comparative paper I'm thinking of.
Godfrey, A. Jonathan R., and M. Theodor Loots. 2014. “Statistical Software (R, SAS, SPSS, and Minitab) for Blind Students and Practitioners.” Journal of Statistical Software, Software Reviews 58 (1): 1–25. https://www.jstatsoft.org/v58/s01
Godfrey, A. Jonathan R. 2013. “Statistical Software from a Blind Person’s Perspective: R Is the Best, but We Can Make It Better.” 2013. The R Journal 5 (1): 73–79. https://journal.r-project.org/archive/2013-1/godfrey.pdf