MySql server does not start on OS Linux-4.17.0-3-amd64-x86_64-with-debian-buster-sid how to solve?

Question

MySQL

[email protected] ~ # journalctl -xe
--
-- Unit mysql.service has failed.
--
-- The result is RESULT.
Jan 04 20:00:35 IMP1 systemd[1]: mysql.service: Service RestartSec=100ms expired, scheduling restart.
Jan 04 20:00:35 IMP1 systemd[1]: mysql.service: Scheduled restart job, restart counter is at 5.
-- Subject: Automatic restarting of a unit has been scheduled
-- Defined-By: systemd
-- Support: https://www.debian.org/support
--
-- Automatic restarting of the unit mysql.service has been scheduled, as the result for
-- the configured Restart= setting for the unit.
Jan 04 20:00:35 IMP1 systemd[1]: Stopped MySQL Community Server.
-- Subject: Unit mysql.service has finished shutting down
-- Defined-By: systemd
-- Support: https://www.debian.org/support
--
-- Unit mysql.service has finished shutting down.
Jan 04 20:00:35 IMP1 systemd[1]: mysql.service: Start request repeated too quickly.
Jan 04 20:00:35 IMP1 systemd[1]: mysql.service: Failed with result 'exit-code'.
Jan 04 20:00:35 IMP1 systemd[1]: Failed to start MySQL Community Server.
-- Subject: Unit mysql.service has failed
-- Defined-By: systemd
-- Support: https://www.debian.org/support
--
-- Unit mysql.service has failed.
--
-- The result is RESULT.

Answer 1

mysqld --validate-config

Answer 2

[email protected] ~ # mysqld --validate-config
mysqld: Error on realpath() on '/var/lib/mysql-files' (Error 2 - No such file or directory)
2021-01-04T17:35:40.416503Z 0 [ERROR] [MY-010095] [Server] Failed to access directory for --secure-file-priv. Please make sure that directory exists and is accessible by MySQL Server. Supplied value : /var/lib/mysql-files
2021-01-04T17:35:40.416517Z 0 [ERROR] [MY-010119] [Server] Aborting
Even before installing apt-get update gave errors:
[email protected] /etc/ apt # apt-get update
Ign httpredir.debian.org jessie -backports InRelease
Ign ftp.debian.org jessie InRelease
Get:1 security.debian.org jessie/updates InRelease [44.9 kB]
Ign httpredir.debian.org jessie -backports Release.gpg
Ign httpredir.debian.org jessie -backports Release
Get:2 ftp.debian.org jessie-updates InRelease [16.3 kB]
Get:3 ftp.de.debian.org buster InRelease [121 kB]
Get:4 ftp.de.debian.org sid InRelease [153 kB]
Get:5 packages.dotdeb.org jessie InRelease [9,839 B]
Get:6 ftp.debian.org jessie Release.gpg [1,652 B]
Get:7 ftp .debian.org jessie Release [77.3 kB]
Err httpredir.debian.org jessie-backports/main amd64 Packages
404 Not Found
Ign httpredir.debian.org jessie -backports/main Translation-en
Get:8 ftp.debian.org jessie- updates/main Sources [20 B]
Get:9security.debian.org jessie/updates/main Sources [366 kB]
Get:10 ftp.debian.org jessie-updates/contrib Sources [20 B]
Get:11 ftp.debian.org jessie-updates/non-free Sources [ 20 B]
Get:12 ftp.debian.org jessie-updates/main amd64 Packages [20 B]
Get:13 ftp.debian.org jessie-updates/contrib amd64 Packages [20 B]
Get:14 ftp.debian.org jessie -updates/non-free amd64 Packages [20 B]
Get:15 ftp.debian.org jessie-updates/contrib Translation-en [14 B]
Get:16 ftp.debian.org jessie-updates/main Translation-en [14 B]
Get:17ftp.debian.org jessie-updates/non-free Translation-en [14 B]
Get:18 security.debian.org jessie/updates/contrib Sources [1,439 B]
Get:19 ftp.de.debian.org buster/main Sources [7,842 kB]
Get:20 security.debian.org jessie/updates/non-free Sources [1,915 B]
Get:21 security.debian.org jessie/updates/main amd64 Packages [781 kB]
Get:22 security.debian .org jessie/updates/contrib amd64 Packages [2,506 B]
Get:23security.debian.org jessie/updates/non-free amd64 Packages [4,702 B]
Get:24 security.debian.org jessie/updates/contrib Translation-en [1,211 B]
Get:25 security.debian.org jessie/updates/ main Translation-en [401 kB]
Get:26 security.debian.org jessie/updates/non-free Translation-en [11.8 kB]
Get:27 ftp.debian.org jessie/main Sources [7,063 kB]
Get:28 packages .dotdeb.orgjessie/all Sources [51.4 kB]
Get:29 packages.dotdeb.org jessie/all amd64 Packages [275 kB]
Get:30 ftp.debian.org jessie/contrib Sources [50.4 kB]
Get:31 ftp.debian.org jessie /non-free Sources [99.2 kB]
Get:32 ftp.de.debian.org buster/contrib Sources [42.5 kB]
Get:33 ftp.debian.org jessie/main amd64 Packages [6,818 kB]
Get:34ftp.de.debian.org buster/non-free Sources [85.6 kB]
Get:35 ftp.de.debian.org buster/main amd64 Packages [7,907 kB]
Get:36 ftp.debian.org jessie/contrib amd64 Packages [ 49.8 kB]
Get:37 ftp.debian.org jessie/non-free amd64 Packages [83.2 kB]
Get:38 ftp.debian.org jessie/contrib Translation-en [38.3 kB]
Ign packages.dotdeb.orgjessie/all Translation-en
Get:39 ftp.debian.org jessie/main Translation-en [4,581 kB]
Get:40 ftp.debian.org jessie/non-free Translation-en [72.0 kB]
Get:41 ftp.de .debian.org buster/contrib amd64 Packages [50.2 kB]
Get:42 ftp.de.debian.org buster/non-free amd64 Packages [87.7 kB]
Get:43 ftp.de.debian.org buster/contrib Translation-en [44.2 kB]
Get:44 ftp.de.debian.orgbuster/main Translation-en [5,971 kB]
Get:45 ftp.de.debian.org buster/non-free Translation-en [88.8 kB]
Get:46 ftp.de.debian.org sid/main amd64 Packages [8,561 kB ]
Get:47 ftp.de.debian.org sid/main Translation-en [6,445 kB]
Fetched 58.3 MB in 6s (8,726 kB/s)
W: There is no public key available for the following key IDs:
648ACFD622F3D138
NO_PUBKEY DCC9EFBF77E11517
W : There is no public key available for the following key IDs:
648ACFD622F3D138
W: Failed to fetch httpredir.debian.org/debian/dists/jessie-backports... 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.