If you're already using Azure, they offer Linux stuff too. You can move away from Windows without moving away from Microsoft (if you want to). Or you can find equivalent services on AWS or Gcloud, or more abstracted ones like Vercel or Netlify (who whitelabel and value-add features & ease of use on top of big clouds).
i'm using azure, aws and gcp at work and personal projects. i recommend azure for better management UX and relatively transparent cost and billing management. once you setup your infrastructure as code you can move anything but the vendor specific services easily. Azure AD is easy to migrate from, API gateway not so much.