But I will continue my story.
 The experiment was continued by me and was crowned with success.  This happened after I wrote a very long and reasoned message to support with links to legislation on personal data and my rights to privacy.  In general, I corresponded with support for about a month.  Eventually, the Blockchain.com technical service changed the email to confirm the login to the wallet and I was finally able to log into it.  So it turned out to be possible. 

Here is the personal data legislations I referred to.  You just need to quote legal norms in your correspondence and everything can work out without any photographs of your face or documents.


REGULATION (EU) 2016/679 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 27 April 2016
on the protection of natural persons with regard to the processing of personal data and on the free movement of such data, and repealing Directive 95/46/EC (General Data Protection Regulation)
(GDPR)

CAYMAN ISLANDS
DATA PROTECTION ACT  (2021 Revision)
Supplement No. 1 published with Legislation Gazette No. 29 dated 30th April, 2021.


I recommend that in your correspondence with support you cite the norm of the third principle (c) (GDPR) of working with personal data. 
This principle is present in the text of both laws.


"CHAPTER II
 Principles
 Article 5
Principles relating to processing of personal data

 1. Personal data shall be:
(a)  processed lawfully, fairly and in a transparent manner in relation to the data subject (‘lawfulness, fairness and transparency’);
(b)  collected for specified, explicit and legitimate purposes and not further processed in a manner that is incompatible with those purposes; further processing for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes shall, in accordance with Article 89(1), not be considered to be incompatible with the initial purposes (‘purpose limitation’);
(c)  adequate, relevant and limited to what is necessary in relation to the purposes for which they are processed (‘data minimisation’);
(d)  accurate and, where necessary, kept up to date; every reasonable step must be taken to ensure that personal data that are inaccurate, having regard to the purposes for which they are processed, are erased or rectified without delay (‘accuracy’);
(e)  kept in a form which permits identification of data subjects for no longer than is necessary for the purposes for which the personal data are processed; personal data may be stored for longer periods insofar as the personal data will be processed solely for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) subject to implementation of the appropriate technical and organisational measures required by this Regulation in order to safeguard the rights and freedoms of the data subject (‘storage limitation’);
(f)  processed in a manner that ensures appropriate security of the personal data, including protection against unauthorised or unlawful processing and against accidental loss, destruction or damage, using appropriate technical or organisational measures (‘integrity and confidentiality’).
......
"