PKCE issues & password authentication

Hi, have been testing this 64.1.0 and found a few issues.

1. Recently refreshed non-preview sandbox: would not work for OAuth nor password authentication. Not sure if it’s just me. No issues with preview sandboxes

Custom URL setting for sandbox format in https://xxxx-xx.sandbox.my.Salesforce.com/

Error: Oauth Webserver with PKCE flow failed

Error: login failed. Please check your username, password, and security token.

2. Password authentication: seems no token required. I only entered password and it allowed me to login. System admin(with whitelisted IP profile)

3. Seems https://test.salesforce.com is no longer working in dataloader settings (has to be my custom domain? ) even though in Salesforce my domain (unchecked - prevent SOAP API login & prevent login from https://test.salesforce.com)
Error: login failed. Please check your username, password, and security token.

Working when changing back to my custom domain