Installing and upgrading help

"... whole server backup running using backup software" ...

and you've tested that?

Actually, maybe a 2nd layer - just moodle stuff ... moodle code, moodledata/filedir/ and DB dump.    You have 2 sites on same server so the following would need to be adjusted for each.

You have to create the backups directory and replace [] below.

As root user:
df -h
That will show how much is used and available.
Your code, db, and moodledata will be in /
You have 2 sites on same server.

So to get exact info
cd /path/to/whereyoucanlsonesite
then 
du -h ./site

That's code.

Find paths to your moodledata directories.   Check config.php file of each site.

Then same:
cd /path/to/whereyoucanlsthemoodledata
then
du -h moodledata/filedir/

DB - mysqldump command to a directory where you are saving the code and minimal moodledata/filedir/

mysqldump --default-character-set=utf8mb4 -u root -p'[password]' [dbname] > [/path/to/]backups/moodle-[moodlevrnumber]-$(date +%Y%m%d%-H%M).sql;

You replace [] above and you create the /path/to/ directory for backups.

For code:
cd /path/to/whereyoucanseemoodlecode
tar -cvf [/path/to/]backups/moodle-[vrnum]-$(date +%Y%m%d%-H%M).tar

will render files something like:

moodle-4116-202502071915.sql
moodle-4116-202502071915.tar

Ditto for moodledata ... 
cd /path/whereyoucanseemoodledata
then
tar -cvf /path/to/backups/moodle-data-[vrnum]-$(date +%Y%m%d%-H%M).tar

'SoS', Ken

Sent you a PM with a reminder.