/data/data/com.termux                       - private Termux directory on internal storage

/sdcard/Android/data/com.termux             - private Termux directory on shared storage

/storage/XXXX-XXXX/Android/data/com.termux  - private Termux directory on external storage, XXXX-XXXX is the UUID of your micro-sd card.

${HOME}/storage/external-1                  - alias for Termux private directory on your micro-sd.

termux-setup-storage

tar -zcf /sdcard/termux-backup.tar.gz -C /data/data/com.termux/files ./home ./usr

termux-setup-storage

termux-restore /sdcard/backup.tar.xz

export GPG_TTY=$(tty)

gpg --decrypt /sdcard/backup.tar.gz.gpg | gunzip | termux-restore -