I'd like to add that so many providers do not support either `prompt=select_account` or just natively ask the user which account to login to, mainly for OIDC. Working with IAM systems at work and using different test accounts, it's frustrating when you can't easily log out of the destination IdP for, say, SSO.
My experience with `prompt=login` is also mixed. Okta's behavior does not indicate which account you're logging into (no username/email address), and only asks to re-input your password. They have a "Back to sign in" link button, but that loses all OAuth context and does not lead you back into the app you're attempting to OAuth into, unless if you specifically override that button to hit Okta's logout endpoint and with a redirect back to your OAuth authorize endpoint/session.
It's janky. And I would know because we had to implement that at work.