Finally could get this worked around. I disabled comments and trackbacks for new posts and enabled automatic disactivation of comments for posts older than 14 days, so all old posts will get configured automatically for no comments. Moreover, I found the option to disable sending of email notifications for each comment, so at least I don’t get junk anymore in my mailbox. Moreover, I found out that GMail has support for filtering emails but only when accessed from gmail.com on a PC, not from the GMail app on a smartphone. Google’s fragmentation (different platforms have different functioanlities) is another issue, completely separate from this one. Also found out that I could create a new database user from my cPanel and bind it to the WP database, so I would then be able to manipulate the DB with SQL queries. I won’t need that for now, but at least it’s possible.