Why is my /var/log folder 118 GB in size?

I am quite new to the aspects of ubuntu although I know the basics. My computer is running low on storage and upon inspection, I have found that my /var/log folder is 118 GB big! I have considered just deleting the logs but I am quite new and it doesn't seem right simply to delete every log, since some programs may not be able to deal with lost log files. The directory itself is 118 GB, which says to me something is wrong, anyway. Under the closer inspection of the logging directory here is what I find:

root@fateh-Inspiron-13-5378:/var/log# ls -la
total 108917496
drwxrwxr-x 16 root syslog 4096 Aug 31 05:26 .
drwxr-xr-x 15 root root 4096 Aug 3 09:41 ..
-rw-r--r-- 1 root root 22073 Aug 28 07:34 alternatives.log
-rw-r--r-- 1 root root 29184 Jul 26 17:57 alternatives.log.1
-rw-r----- 1 root adm 1734 Aug 27 20:15 apport.log
-rw-r----- 1 root adm 1169 Aug 20 09:56 apport.log.1
-rw-r----- 1 root adm 1055 Aug 13 15:21 apport.log.2.gz
-rw-r----- 1 root adm 125 Jul 30 08:30 apport.log.3.gz
-rw-r----- 1 root adm 124 Jul 29 16:01 apport.log.4.gz
-rw-r----- 1 root adm 247 Jul 28 09:49 apport.log.5.gz
drwxr-xr-x 2 root root 4096 Aug 31 06:14 apt
-rw-r----- 1 syslog adm 713367 Aug 31 12:11 auth.log
-rw-r----- 1 syslog adm 503808 Aug 24 00:00 auth.log.1
-rw-r----- 1 syslog adm 71547 Aug 18 05:24 auth.log.2.gz
-rw-r----- 1 syslog adm 11627 Aug 1 23:36 auth.log.3.gz
-rw------- 1 root root 322337 Aug 31 05:26 boot.log
-rw------- 1 root root 216534 Aug 24 00:00 boot.log.1
-rw------- 1 root root 583044 Aug 18 05:24 boot.log.2
-rw------- 1 root root 42659 Aug 4 00:00 boot.log.3
-rw------- 1 root root 10452 Aug 2 00:00 boot.log.4
-rw------- 1 root root 18801 Jul 27 00:00 boot.log.5
-rw-r--r-- 1 root root 104003 Apr 23 00:33 bootstrap.log
-rw-rw---- 1 root utmp 1152 Aug 22 11:51 btmp
-rw-rw---- 1 root utmp 0 Apr 23 00:32 btmp.1
drwxr-xr-x 2 root root 4096 Aug 28 14:21 cups
drwxr-xr-x 2 root root 4096 Apr 8 08:59 dist-upgrade
-rw-r--r-- 1 root adm 84351 Aug 31 05:26 dmesg
-rw-r--r-- 1 root adm 87800 Aug 30 18:35 dmesg.0
-rw-r--r-- 1 root adm 21453 Aug 30 07:28 dmesg.1.gz
-rw-r--r-- 1 root adm 21348 Aug 30 06:28 dmesg.2.gz
-rw-r--r-- 1 root adm 21403 Aug 29 14:10 dmesg.3.gz
-rw-r--r-- 1 root adm 21271 Aug 29 10:48 dmesg.4.gz
-rw-r--r-- 1 root root 612124 Aug 31 06:15 dpkg.log
-rw-r--r-- 1 root root 1193854 Jul 31 06:48 dpkg.log.1
-rw-r--r-- 1 root root 2049792 Aug 12 10:40 faillog
-rw-r--r-- 1 root root 11453 Aug 22 07:11 fontconfig.log
drwx--x--x 2 root gdm 4096 Oct 7 2019 gdm3
-rw-r--r-- 1 root root 1242 Aug 31 05:26 gpu-manager.log
drwxr-xr-x 3 root root 4096 Apr 23 00:36 hp
drwxrwxr-x 2 root root 4096 Jul 25 08:12 installer
drwxr-sr-x+ 3 root systemd-journal 4096 Jul 25 08:13 journal
-rw-r----- 1 syslog adm 5050809 Aug 31 12:07 kern.log
-rw-r----- 1 syslog adm 55699410944 Aug 23 22:50 kern.log.1
-rw-r----- 1 syslog adm 1525796 Aug 18 05:24 kern.log.2.gz
-rw-r----- 1 syslog adm 188167 Aug 1 23:53 kern.log.3.gz
-rw-rw-r-- 1 root utmp 18704352 Aug 12 10:40 lastlog
drwxr-xr-x 5 root root 4096 Aug 12 10:40 libvirt
drwxr-x--- 2 www-data www-data 4096 Aug 24 00:00 lighttpd
drwxr-xr-x 2 root root 4096 Sep 5 2019 openvpn
drwxr-xr-x 2 pihole pihole 4096 Aug 12 14:15 pihole
-rw-r--r-- 1 pihole pihole 17216 Aug 31 12:00 pihole-FTL.log
-rw-r--r-- 1 pihole pihole 89319 Aug 30 06:28 pihole-FTL.log.1
-rw-r--r-- 1 pihole pihole 2326 Aug 24 00:00 pihole-FTL.log.2.gz
-rw-r--r-- 1 pihole pihole 28126 Aug 23 06:50 pihole-FTL.log.3.gz
-rw-r--r-- 1 pihole pihole 2113 Aug 31 12:00 pihole.log
-rw-r--r-- 1 pihole pihole 6294 Aug 31 05:26 pihole.log.1
-rw-r--r-- 1 pihole pihole 3967 Aug 30 06:28 pihole.log.2.gz
-rw-r--r-- 1 pihole pihole 1595 Aug 29 07:11 pihole.log.3.gz
-rw-r--r-- 1 pihole pihole 510 Aug 28 05:24 pihole.log.4.gz
-rw-r--r-- 1 pihole pihole 2201 Aug 27 05:22 pihole.log.5.gz
drwx------ 2 root root 4096 Apr 23 00:32 private
drwx------ 2 speech-dispatcher root 4096 Jan 19 2020 speech-dispatcher
-rw-r----- 1 syslog adm 50371538 Aug 31 12:11 syslog
-rw-r----- 1 syslog adm 55744626688 Aug 24 00:00 syslog.1
-rw-r----- 1 syslog adm 23788290 Aug 18 05:24 syslog.2.gz
-rw-r----- 1 syslog adm 669055 Aug 4 00:00 syslog.3.gz
-rw-r----- 1 syslog adm 163942 Aug 3 00:00 syslog.4.gz
-rw-r----- 1 syslog adm 158326 Aug 2 00:00 syslog.5.gz
-rw-r----- 1 syslog adm 116667 Aug 1 00:00 syslog.6.gz
-rw-r----- 1 syslog adm 81773 Jul 31 00:00 syslog.7.gz
-rw------- 1 root root 0 Apr 23 00:33 ubuntu-advantage.log
drwxr-x--- 2 root adm 4096 Aug 4 00:00 unattended-upgrades
-rw-r--r-- 1 root root 102 Aug 12 05:33 vbox-setup.log
-rw-r--r-- 1 root root 102 Aug 11 20:21 vbox-setup.log.1
-rw-r--r-- 1 root root 102 Aug 11 14:33 vbox-setup.log.2
-rw-r--r-- 1 root root 102 Aug 11 12:21 vbox-setup.log.3
-rw-r--r-- 1 root root 102 Aug 11 08:54 vbox-setup.log.4
-rw-rw-r-- 1 root utmp 153600 Aug 31 05:26 wtmp

Where the important logs are:

-rw-r----- 1 syslog adm 55699410944 Aug 23 22:50 kern.log.1
-rw-r----- 1 syslog adm 55744626688 Aug 24 00:00 syslog.1

as well as some other not so big ones. What can be wrong? Should I just clean the files with cat /dev/null > kern.log.1 and cat /dev/null > syslog.1 or is there a deeper problem with these logs?

Know someone who can answer? Share a link to this question via email, Twitter, or Facebook.