You work at a company and some pages of the website aren't addressing accessibility concerns. You don't own those pages, but would like to advocate for accessibility at your company. Here's a guide on how to advocate for accessibility at your company.

Legal exposure

Digital accessibility is a legal requirement as put forth by the Americans with Disabilities Act (ADA).

In February [2023], 181 lawsuits were filed. 86% were filed in New York; MARS KHAIMOV LAW, PLLC filed 47 lawsuits in New York; 7 Plaintiffs filed 44% of lawsuits; and 17% of the litigated websites used overlay tools.
~ https://www.accessibility.com/digital-lawsuits

It's important that companies take accessibility issues seriously because users do. Accessibility is not a nice to have it is a legal requirement like GDPR and privacy compliance.

Build reports

Create a metric that teams can use to move a needle and prove progress. You could use Lighthouse to help you accessibility audit single pages. If you need to do something more at scale and can code you could build an accessibility checker

Path to Success

Once an organization is convinced to make the investment here are some resources to help build on that success and scope work.
IBM Equal Access Toolkit will help you to plan, design, develop, verify, and launch accessible digital products. There is also the A11y Project who also build accessibility tooling and resources.