The line
cryptsetup --type luks2 --cipher xchacha20,aes-adiantum-plain64 --hash sha256 --iter-time 5000 –keysize 256 --pbkdf argon2i luksFormat /dev/mmcblk0p2
should be
cryptsetup --type luks2 --cipher xchacha20,aes-adiantum-plain64 --hash sha256 --iter-time 5000 --key-size 256 --pbkdf argon2i luksFormat /dev/mmcblk0p2
(the option separator for "key-size" should be two hyphens instead of one en dash and the "key-size" option has a hyphen, i.e. "key-size" instead of "keysize")
The line
cryptsetup --type luks2 --cipher xchacha20,aes-adiantum-plain64 --hash sha256 --iter-time 5000 –keysize 256 --pbkdf argon2i luksFormat /dev/mmcblk0p2should be
cryptsetup --type luks2 --cipher xchacha20,aes-adiantum-plain64 --hash sha256 --iter-time 5000 --key-size 256 --pbkdf argon2i luksFormat /dev/mmcblk0p2(the option separator for "key-size" should be two hyphens instead of one en dash and the "key-size" option has a hyphen, i.e. "key-size" instead of "keysize")