Question
You ran some cryptsetup commannds. You passed no --type flag. Was the format luks1 or luks2 or something else?
Answer
luks2.
…more recent Ubuntu releases default to version 2 ("luks2").
https://help.ubuntu.com/community/Full_Disk_Encryption_Howto_2019
As of 2022, you may want to use luks2 when you can -- but do not assume you can. That is, sometimes you still need to use luks1. (See the above link as an example of when you need to use luks1.) Another external page that discusses this is here.
Also the mkfs.vfat -F 16 -n EFI-SP ${DEVP}3 command in the above directions may be wrong. You may need to find the /dev/mapper/foobar value. Run this: ls /dev/mapper/ Which of those files is the correct one you want to make a file system on? You may need to change ${DEVP}3 with the full path /dev/mapper/foobar (where /dev/mapper/foobar is the intended file system).