Other places to check:
- If you’re on an Nginx server, check the server config
- Deactivate all plugins and switch to a default theme
- If you use a host with a control panel, check there for hidden redirects
Each time you make a change, use an Incognito window or a header check tool to verify – your browser caches redirects so it may be fixed even when your browser is taking you through the old redirects.