How to extract data from a VPS due to SSH blocked?

Question

SSH

The following situation has arisen. I found a friend who helped me get acquainted with VPS servers. Then it was "just so" interesting, but now I think how they can be used. But it so happened that this acquaintance either started off, or something happened in life, but the connection with him disappeared for a while, once I managed to contact him and he said that I was to blame for everything. In what he did not specify and the connection was cut off completely. But that's not important.
Before the "incident" he installed a couple of programs, but he made access to my VPS through SHH, of course he didn't give me the keys. And now, after a while, I tried to log into my VPS using the VNC host, the connection was established successfully. But the problem is that through it you can’t extract the necessary information in any way. I managed to install MC and I think I found the keys. Question.
one)How can I log into the VPS other than the VNC host, so much so as to bypass the SHH keys?
2) I was able to open the alleged key file in MC, explain how you can copy the information to a PC? And what keys should be pressed when the command "M-6 copy text"?
3) Is it possible to establish an FTP or WebDAV connection without SSH?
4) Suppose I found the SHH key files and copied them in some classical way, what program can I establish a connection with the VPS by inserting SSH and how?
I only recently started to get acquainted with VPS, a humanist by education, please help me figure it out.

Answer 1

Stop storing child porn on a friend's server. He's already been sent through the stage.

Answer 2

Ie take a screenshot and recognize the text on it, the author did not guess?
VNC is like a graphical interface, but a lot can be done through it - if there is no external address (vps was not paid) - then you can upload it somewhere where this external address is - on the same Yandex via webdav. And if there is an external address, then raising a web / ftp server is not a problem at all - and downloading from it.
Apparently the author needs an experienced mentor who will tell you what and how. The acquaintance was apparently tired of misunderstanding and spat on it.
If you can’t get it yourself, then you can pay and they will do everything.

Answer 3

Remove authorization by VNC only by key, add authorization by password, change the password. Log in with a password using ssx. See /etc/ssh_sshd_config