I'm not sure your organization's setup with Netlify but isn't the whole point of Serverless to be... "serverless"? I could migrate twice the amount of properties you have to another provider in less than 3 hours...
I get your frustration but maybe cut some slack. If anything is mission critical, you should have had a backup plan if Netlify, Vercel, Cloudflare, or something else.
We use(d) Netlify for the frontend. I agree, our mistake was believing Netlify could be used for more than toy websites and took care of backup plans for us. Clearly they do not.
It's not just migrating the front-end if they're also using other functionalities like Netlify functions, forms, authentications etc. Netlify is not just static file hosting.
I get your frustration but maybe cut some slack. If anything is mission critical, you should have had a backup plan if Netlify, Vercel, Cloudflare, or something else.