Ovi,
Thank you very much for your feedback! I have shared a link to the post with Plesk Team.
My plesure, I'm glad you found my feedback useful. Now re:
1) Thanks for your suggestion but I prefer to not log in as root, even over ssh and with a keypair.
Indeed ssh with sudo is a much better option and it works well for me (I din't think about this, thanks!)
-> The reason why I want to add rw permission to ubuntu user is because I can't browse /var/www/vhosts/mywebsites.tld/httpdocs The folders for my 2 websites are owned by psaserv user and it won't allow any file browsing to ubuntu user. So I queried psaserv groups:
$ grep psaserv /etc/group
psaserv:x: 1003: psaadm,psaftp,www-data,nginx
And then I added ubuntu to all 4 of them: sudo usermod -a -G psaadm ubuntu [x4]
However, after this process, I still can't browse the website files with ubuntu user over SSH in Filezilla. I can browse all the other files and folders, just not the ones owned by psaserv.
2) I plan to use another instance as a mail server. Or maybe I'll just continue to pay my old shared host for mail service.. Either way, the answer is no, not on this instance.
3 & 4) Super, thanks, all good now.
5) Thanks, but it still doesn't work on WP:
http://tinyimg.io/i/7g4RSQC.png
And I tried PHP 7, 7.1 and 7.2 with all 3 options. The fastest is PHP 7.1 with FPM by Apache.
Best wishes,
Ovi