Issue HTTP ERROR 500 - .deb packages/.rpm ??

[resurge121]

Hi Plesk People,
Please I'm having consistent problems with this panel!
I couldn't access my wp-admin so I restarted my server, then I couldn't access my Plesk panel or the wp site: Error establishing a database connection
I asked the hosting support, they just sent me Plesk documentation, when Applied I got some errors.>> https://support.plesk.com/hc/en-us/...lesk-Server-Error-500-Service-Agent-Exception
.
After Connecting to The server via SSH
I got this:

root@MeditationFlow:~# rpm -Uvh --force plesk-service-node-utilities-17.8.11-cos7.build1708180515.21.x86_64.rpm

Command 'rpm' not found, but can be installed with:

apt install rpm

root@MeditationFlow:~#
root@MeditationFlow:~# cd /root/.ssh/
root@MeditationFlow:~/.ssh# rpm -Uvh --force plesk-service-node-utilities-17.8.11-cos7.build1708180515.21.x86_64.rpm

Command 'rpm' not found, but can be installed with:

apt install rpm

root@MeditationFlow:~/.ssh# ^C
root@MeditationFlow:~/.ssh# ^C
root@MeditationFlow:~/.ssh# apt install rpm
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
debugedit libdw1 libnspr4 libnss3 librpm8 librpmbuild8 librpmio8 librpmsign8
rpm-common rpm2cpio
Suggested packages:
rpm-i18n alien python elfutils rpmlint rpm2html
The following NEW packages will be installed:
debugedit libdw1 libnspr4 libnss3 librpm8 librpmbuild8 librpmio8 librpmsign8
rpm rpm-common rpm2cpio
0 upgraded, 11 newly installed, 0 to remove and 11 not upgraded.
Need to get 2,093 kB of archives.
After this operation, 7,506 kB of additional disk space will be used.
E: You don't have enough free space in /var/cache/apt/archives/.
root@MeditationFlow:~/.ssh#

The Hosting support replied

From this output it appears that you have connected to the instance successfully. However, please note that a .rpm file such as this is the incorrect package type for an instance running Ubuntu. Ubuntu uses .deb packages by default. We recommend finding a .deb version of this package if possible.

However, installation of software packages is beyond the scope of our support.

I'm not a tech, so please if anyone can guide me or Can Give me some code or...
All I want is to get some important data from my site, and I will make sure this is the last time I use Plesk or Vultur!
My Plesk login URL: https://meditationflow.org:8443/smb/web/view
Thanks