Jessica

Any update on the fix because WordPress support states the problem still exists:

You'll want to thoroughly review any custom code for inefficiencies as it's outside our Scope of Support. That said, we can tell you that our built-in caching is not working and bypassed from PHP sessions always being created on every page load as well as cookies being set named guest_id and mwai_session_id. These cookies are from the following plugins:
ai-engine
 
We'd recommend deleted or modifying these plugins to not set cookies if you want cache to work. Afterwards, you could then determine where the PHP sessions are being created in your code. This guide outlines a general process for checking cookies/sessions that will break cache causing performance issues: https://developer.wordpress.com/docs/troubleshooting/site-performance/#7-practical-steps-to-optimize-ttfb-on-wordpress-com
 
Searching for session_start functions in plugins, these are just a few you may want to test deactivating to see if cache then works: 
ai-engine

Identify Relevant Meta Keys: You want to delete the following meta keys:
_two_factor_nonce
_two_factor_last_login_failure
_two_factor_failed_login_attempts
_two_factor_fido_u2f_register_request
_two_factor_backup_codes
_two_factor_enabled_providers
_two_factor_provider

Run SQL Queries to Delete 2FA Data: You can delete the data for the specific user by running the following SQL queries. Replace 1 with the actual user_id of the user affected.

Run SQL Queries:

DELETE FROM wp_usermeta WHERE user_id = 1 AND meta_key = '_two_factor_nonce';
DELETE FROM wp_usermeta WHERE user_id = 1 AND meta_key = '_two_factor_last_login_failure';
DELETE FROM wp_usermeta WHERE user_id = 1 AND meta_key = '_two_factor_failed_login_attempts';
DELETE FROM wp_usermeta WHERE user_id = 1 AND meta_key = '_two_factor_fido_u2f_register_request';
DELETE FROM wp_usermeta WHERE user_id = 1 AND meta_key = '_two_factor_backup_codes';
DELETE FROM wp_usermeta WHERE user_id = 1 AND meta_key = '_two_factor_enabled_providers';
DELETE FROM wp_usermeta WHERE user_id = 1 AND meta_key = '_two_factor_provider';

These queries will delete the 2FA-related data for the user with user_id = 1. Make sure to adjust the user_id if needed.

Verify the Deletion: After running the queries, you can verify that the rows have been deleted by running:
SELECT * FROM wp_usermeta WHERE user_id = 1 AND meta_key LIKE ‘_two_factor%’;