I had the problem with a not "clean" unmounted SSD (MySql-Data)
The warning (not error) message I see in your screenshot is:
Setting lower_case_table_names=2 because filesystem for /mnt/Phaselis_1/mysql-data is case insensitive
Programs usually don't stop on warning messages so this one is a bit weird.
What filesystem is this? Please run mount | grep /mnt/Phaselis_1/mysql-data and paste the output here.
After a power outage it might make sense to run a fsck.ext4 /dev/your-device-file, provided your filesystem is ext4.
Please also provide the logs from /var/log/syslog or journalctl or /var/log/mysql/*log
I tried to solve the problem using by removing the directory "mysql-data" (rm .rf /mnt/myData/mysql-data) - this had worked in a previous case, but not now.
/mnt/myData/mysql-data is not the same directory, or the same mount point, as /mnt/Phaselis_1/mysql-data. Are you talking about the same disk / device?
This sounds like you deleted all of the mysql data - is that correct? As in, you want to install mariadb-server from scratch and get rid of all the old data?