Mariadb server won't restart

I saw that my website was down, and so I foolishly restarted my Linode. (Debian 9, running MariaDB and a PHP website). Now I see that the problem was that my database was non-responsive. I can't get my MariaDB back up again. When I run systemctl restart mariadb, I get: "Job for mariadb.service has failed because the control process exited with error code. See systemctl status mariadb.service and journalctl -xe for details."

Output of systemctl status mariadb:

● mariadb.service - MariaDB 10.1.44 database server
Loaded: loaded (/lib/systemd/system/mariadb.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Sat 2020-08-29 19:46:57 CDT; 2min 23s ago
Docs: man:mysqld(8)
https://mariadb.com/kb/en/library/systemd/
Process: 4810 ExecStart=/usr/sbin/mysqld $MYSQLD_OPTS $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION (code=exited, status=1/FAILURE)
Process: 4718 ExecStartPre=/bin/sh -c [ ! -e /usr/bin/galera_recovery ] && VAR= || VAR=/usr/bin/galera_recovery; [ $? -eq 0 ] &&
Process: 4712 ExecStartPre=/bin/sh -c systemctl unset-environment _WSREP_START_POSITION (code=exited, status=0/SUCCESS)
Process: 4711 ExecStartPre=/usr/bin/install -m 755 -o mysql -g root -d /var/run/mysqld (code=exited, status=0/SUCCESS)
Main PID: 4810 (code=exited, status=1/FAILURE)
Status: "MariaDB server is down"

Aug 29 19:46:53 mnminimarket systemd[1]: Starting MariaDB 10.1.44 database server…
Aug 29 19:46:54 mnminimarket mysqld[4810]: 2020-08-29 19:46:54 139732841295232 [Warning] option 'table_open_cache': unsigned value 335544
Aug 29 19:46:54 mnminimarket mysqld[4810]: 2020-08-29 19:46:54 139732841295232 [Note] /usr/sbin/mysqld (mysqld 10.1.44-MariaDB-0+deb9u1)
Aug 29 19:46:54 mnminimarket mysqld[4810]: 2020-08-29 19:46:54 139732841295232 [Warning] Could not increase number of max_open_files to m
Aug 29 19:46:57 mnminimarket systemd[1]: mariadb.service: Main process exited, code=exited, status=1/FAILURE
Aug 29 19:46:57 mnminimarket systemd[1]: Failed to start MariaDB 10.1.44 database server.
Aug 29 19:46:57 mnminimarket systemd[1]: mariadb.service: Unit entered failed state.
Aug 29 19:46:57 mnminimarket systemd[1]: mariadb.service: Failed with result 'exit-code'.

Output of journaltcl -xe:

Aug 29 19:46:53 mnminimarket systemd[1]: Starting MariaDB 10.1.44 database server…
-- Subject: Unit mariadb.service has begun start-up
-- Defined-By: systemd

-- Support: https://www.debian.org/support

-- Unit mariadb.service has begun starting up.
Aug 29 19:46:54 mnminimarket mysqld[4810]: 2020-08-29 19:46:54 139732841295232 [Warning] option 'table_open_cache': unsigned value 335544
Aug 29 19:46:54 mnminimarket mysqld[4810]: 2020-08-29 19:46:54 139732841295232 [Note] /usr/sbin/mysqld (mysqld 10.1.44-MariaDB-0+deb9u1)
Aug 29 19:46:54 mnminimarket mysqld[4810]: 2020-08-29 19:46:54 139732841295232 [Warning] Could not increase number of max_open_files to m
Aug 29 19:46:57 mnminimarket systemd[1]: mariadb.service: Main process exited, code=exited, status=1/FAILURE
Aug 29 19:46:57 mnminimarket systemd[1]: Failed to start MariaDB 10.1.44 database server.
-- Subject: Unit mariadb.service has failed
-- Defined-By: systemd

-- Support: https://www.debian.org/support

-- Unit mariadb.service has failed.

-- The result is failed.
Aug 29 19:46:57 mnminimarket systemd[1]: mariadb.service: Unit entered failed state.
Aug 29 19:46:57 mnminimarket systemd[1]: mariadb.service: Failed with result 'exit-code'.
Aug 29 19:49:20 mnminimarket sudo[4839]: amanda : TTY=pts/0 ; PWD=/home/amanda ; USER=root ; COMMAND=/bin/systemctl status mariadb
Aug 29 19:49:20 mnminimarket sudo[4839]: pam_unix(sudo:session): session opened for user root by amanda(uid=0)
Aug 29 19:49:35 mnminimarket sshd[4842]: Received disconnect from 222.186.31.83 port 64565:11: [preauth]
Aug 29 19:49:35 mnminimarket sshd[4842]: Disconnected from 222.186.31.83 port 64565 [preauth]
Aug 29 19:49:47 mnminimarket sshd[4844]: Connection closed by 134.175.249.84 port 49370 [preauth]
Aug 29 19:50:00 mnminimarket sudo[4839]: pam_unix(sudo:session): session closed for user root

I've tried several of the fixes on this page, https://mariadb.com/kb/en/what-to-do-if-mariadb-doesnt-start/, namely ProtectSystem=Off, TimeoutStartSec=infinity, TimeoutStopSec=infinity.

I have a hunch it has something to do with the fact that I was getting a 'Too many connections' error in my logs sometimes before the timeout. But now I can't even get my db to start at all to try to fix that issue.