How to release the disk space of Linux home directory under another system

I have a SSD with an Ubuntu system, but for some reason the disk space is full. Now it is impossible to enter the system normally. How can I release disk space and reenter the system normally? This is the display of output under the SSD home directory

Filesystem     1K-blocks     Used Available Use% Mounted on
udev             4003888        0   4003888   0% /dev
tmpfs             807824     3456    804368   1% /run
/dev/sda2       39110168 21066332  16027428  57% /
tmpfs            4039104        0   4039104   0% /dev/shm
tmpfs               5120        4      5116   1% /run/lock
tmpfs            4039104        0   4039104   0% /sys/fs/cgroup
/dev/loop1           128      128         0 100% /snap/bare/5
/dev/loop0        382848   382848         0 100% /snap/anbox/186
/dev/loop2        119552   119552         0 100% /snap/core/14399
/dev/loop3        119552   119552         0 100% /snap/core/14447
/dev/loop4         56960    56960         0 100% /snap/core18/2667
/dev/loop5         56960    56960         0 100% /snap/core18/2679
/dev/loop6         64768    64768         0 100% /snap/core20/1738
/dev/loop8         74752    74752         0 100% /snap/core22/484
/dev/loop7         64896    64896         0 100% /snap/core20/1778
/dev/loop11         8576     8576         0 100% /snap/evince/1017
/dev/loop9         74752    74752         0 100% /snap/core22/504
/dev/loop10        56448    56448         0 100% /snap/cups/872
/dev/loop12         5248     5248         0 100% /snap/evince/1020
/dev/loop13       168832   168832         0 100% /snap/gnome-3-28-1804/161
/dev/loop14       224256   224256         0 100% /snap/gnome-3-34-1804/72
/dev/loop15       224256   224256         0 100% /snap/gnome-3-34-1804/77
/dev/loop16       354688   354688         0 100% /snap/gnome-3-38-2004/115
/dev/loop22       180224   180224         0 100% /snap/musescore/228
/dev/loop23        14848    14848         0 100% /snap/simple-scan/785
/dev/loop17       354688   354688         0 100% /snap/gnome-3-38-2004/119
/dev/loop24        47104    47104         0 100% /snap/snap-store/638
/dev/loop21        83328    83328         0 100% /snap/gtk-common-themes/1534
/dev/loop26        14208    14208         0 100% /snap/simple-scan/769
/dev/loop18       457088   457088         0 100% /snap/gnome-42-2204/44
/dev/loop19       463360   463360         0 100% /snap/gnome-42-2204/56
/dev/loop20        93952    93952         0 100% /snap/gtk-common-themes/1535
/dev/loop25        47104    47104         0 100% /snap/snap-store/599
/dev/loop27        50816    50816         0 100% /snap/snapd/17883
/dev/loop28        51072    51072         0 100% /snap/snapd/17950
/dev/loop31       302848   302848         0 100% /snap/vlc/2344
/dev/loop32       328192   328192         0 100% /snap/vlc/3078
/dev/loop30       384128   384128         0 100% /snap/telegram-desktop/4486
/dev/loop29       384128   384128         0 100% /snap/telegram-desktop/4470
/dev/sda4       29398012 26514444   1367180  96% /home
/dev/sda1         495648    11408    484240   3% /boot/efi
tmpfs             807820       40    807780   1% /run/user/1000

sdb is the SSD