What users need to be created and how to set them up on the Centos web server?

Question

linux

Hello.
There is a VPS from DigitalOcean. There are 10-15 personal sites on the server and a couple of others.
Installed: nginx (backend and static processing), apache (frontend), php, mysql, phpmyadmin.
Only I have and will have access to the server, but it may be necessary for a couple of people to give ftp access to the directories of their sites.
I store all sites in /home/sites.
Actually, the questions are:
1) Which ftp server is better and easier: vsftpd or proftpd? I tried both and both could not be configured properly (there were problems with user rights and setting directory rights, I hope the second attempt will be more successful).
2) What groups and what users should be created for apache, nginx, mysql and ftp? Which user should have what rights, which directories should have access and how to do it all?
3) Maybe it's better to store all your sites in /home/sites/my_user, and others in /home/sites/username?
4) After reading articles about setting up web servers, linux disabled root and I go to Putty through another user, if necessary, I write sudo before the command. But with this configuration, firezill cannot edit the server configuration files in the /etc directories and so on. I understand that you can set up a server as root and then disable it and not edit anything else via sftp, but I highly doubt that the day will come when I put an end to the server setup. The scheme “logged into the console through the second account, wrote sudo vi /etc/ssh/sshd_config, enabled root, logged in through root, edited configs, relogged through the second account, wrote sudo vi /etc/ssh/sshd_config, turned off root” is very dreary. How to be here? Maybe there is an analogue of the sudo console subscript for sftp? :)

Answer 1

1) I use proftpd with access control. Of my clients, only one uses FTP, he has no problems, all rights are configured correctly.
2) Each client has its own folder in home, because I only use nginx, then it and php-fpm are configured to work under the rights of this particular user. So far there haven't been any problems.
3) Regarding the root, what prevents _login_ under an unprivileged one and execute su root in the console
4) All these web muzzles are in the sink, only the console, so that the admin understands what he is doing and how.
PS For the sake of Kholivar - I'm for Debian! V_les this centos!