mount shows this:
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
sys on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
dev on /dev type devtmpfs (rw,nosuid,relatime,size=8068528k,nr_inodes=2017132,mode=755,inode64)
run on /run type tmpfs (rw,nosuid,nodev,relatime,mode=755,inode64)
efivarfs on /sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,noexec,relatime)
/dev/sdd2 on / type ext4 (rw,noatime,commit=60)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,inode64)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
cgroup2 on /sys/fs/cgroup type cgroup2 (rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
bpf on /sys/fs/bpf type bpf (rw,nosuid,nodev,noexec,relatime,mode=700)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=35,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=19493)
mqueue on /dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,nosuid,nodev,relatime,pagesize=2M)
debugfs on /sys/kernel/debug type debugfs (rw,nosuid,nodev,noexec,relatime)
tracefs on /sys/kernel/tracing type tracefs (rw,nosuid,nodev,noexec,relatime)
fusectl on /sys/fs/fuse/connections type fusectl (rw,nosuid,nodev,noexec,relatime)
configfs on /sys/kernel/config type configfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /tmp type tmpfs (rw,noatime,inode64)
/dev/sdc1 on /mnt/x/2 type ext4 (rw,noatime,commit=60,stripe=8191)
/dev/sdd3 on /boot/efi type vfat (rw,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro)
/dev/sdc1 on /home type ext4 (rw,noatime,commit=60,stripe=8191)
/dev/sda4 on /mnt/x/1 type ext4 (rw,noatime,commit=60)
/dev/sdc1 on /mnt/g/2 type ext4 (rw,noatime,commit=60,stripe=8191)
/dev/sdc1 on /mnt/g/2i type ext4 (rw,noatime,commit=60,stripe=8191)
/dev/sdc1 on /mnt/o/2 type ext4 (rw,noatime,commit=60,stripe=8191)
/dev/sdc1 on /opt/shiarta type ext4 (rw,noatime,commit=60,stripe=8191)
/dev/sda4 on /mnt/g/1 type ext4 (rw,noatime,commit=60)
/dev/sda4 on /mnt/o/1 type ext4 (rw,noatime,commit=60)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,nosuid,nodev,noexec,relatime)
tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,size=1616016k,nr_inodes=404004,mode=700,uid=1000,gid=1000,inode64)
gvfsd-fuse on /run/user/1000/gvfs type fuse.gvfsd-fuse (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)
portal on /run/user/1000/doc type fuse.portal (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)
I did do several things with a Live-USB indeed, but that one seems to be able to access the disks properly.