The manual disagrees with you and recommends 143. Use 110 for POP, 587 for SMTP. All with STARTTLS. Only use 993/995/465 if your client is ancient and doesn’t support STARTTLS.
Ahh it can send and receive mail but I do not think I need to send mail thru my client program.
If I going to need to send anything I do that from webmail
Yes, both will work. The phrasing of the manual suggests that IMAPS/993 is a legacy method, and may not be supported in the future, which is why I prefer STARTTLS/143. But certainly on NS7, both work fine.