FYI, in 2024, I still succeed to sync mails on N9 for 2 of my accounts : the yahoo.com and orange.fr accounts. BUT in both cases, i had to use a generated "Application Code" (instead of my passwords). Plus their regular imap and smtp settings of course.
The one that fails nowadays for me is "outlook.com". I suspect they use now too much modern technologies (OAuth2.0, TLS1.2...?). Would you have any idea for "hacking" this case ?