Can I apply/switch to ADR route inside of the UK?
No, the ADR route is only available to applicants from outside the UK. You will not be able to switch to this route from inside the UK. The Home Office will, however, consider applications from those raising similar arguments from within the UK; this happens on an exceptional basis, with cases being considered outside published Immigration Rules. It is only recommended to do this if the applicant can evidence significant health or care needs.