xargs not splitting on whitespace from aws cli output - bash

Question

This commands returns all the AWS regions separated by whitespace:
aws ec2 describe-regions --query 'Regions[*].RegionName' --output text
eu-north-1 ap-south-1 eu-west-3 eu-west-2 eu-west-1 ap-northeast-2 ap-northeast-1 sa-east-1 ca-central-1 ap-southeast-1 ap-southeast-2 eu-central-1 us-east-1 us-east-2 us-west-1 us-west-2
I'm trying to pipe this to xargs but it's seeing it as a single string:
aws ec2 describe-regions --query 'Regions[*].RegionName' --output text | gxargs -I {} aws cloudformation list-stacks --region {}
Invalid endpoint: https://cloudformation.eu-north-1 ap-south-1 eu-west-3 eu-west-2 eu-west-1 ap-northeast-2 ap-northeast-1 sa-east-1 ca-central-1 ap-southeast-1 ap-southeast-2 eu-central-1 us-east-1 us-east-2 us-west-1 us-west-2.amazonaws.com
gxargs: aws: exited with status 255; aborting
gxargs is just gnu xargs (I'm on Mac).
Also, tried this to use jmespath to create a string from an array with a specific delimiter (which I could use with xargs):
aws ec2 describe-regions --query 'Regions[*].join(",",#.RegionName)'
In function join(), invalid type for value: None, expected one of: ['string'], received: "null"
EDIT: just following up, this is what I wound up with. It insists on throwing an error when it doesn't find a stack- probably the same for other aws cli commands
aws ec2 describe-regions --query 'Regions[*].RegionName' --output text | gxargs -n 1 sh -c 'aws cloudformation describe-stacks --stack-name findme --region $0 || true'

Answer 1

Here's man xargs for -I:
-I replace-str
Replace occurrences of replace-str in the initial-arguments with names read from standard input. Also, unquoted blanks
do not terminate input items; instead the separator is the newline character. Implies -x and -L 1.
You can use xargs -n 1 aws cloudformation list-stacks --region instead