Google Takeout Merge Tool: Unzips and merges all your exported data into a single folder

takeout-merge.sh

#!/usr/bin/env bash

destDir="../Takeout-merge"
mkdir -p $destDir

# Merges the different unzipped Takeout folders into one

for p in $(seq -f "%03g" 1 ${1:-1}); do
	if [ -f $p/DONE ]; then
		echo "Skipping $p/Takeout ... "
		continue
	fi
	echo "Merging $p/Takeout into {$destDir} ... "
	# t = preserve modification times
	# q = quiet, suppress non-error messages
	# r = recursive on folders
	# X = preserved extended attributes
	# X = skip files which are newer in dest than in src
	# h = output numbers in a human-readable format
	rsync -rtXhu --info=progress2 --safe-links --remove-source-files $p/Takeout {$destDir}
	touch "$p/DONE"
	echo "DONE merging $p"
done

echo "ALL MERGED!"

takeout-unzip.sh

#!/usr/bin/env bash

# Unzips all Takeout archive files (living in the same dir)

archiveTimestamp=${2:-"20000101T100000Z"}

for p in $(seq -f "%03g" 1 ${1:-1}); do
  f="takeout-${archiveTimestamp}-$p.tgz"
  if [ -f $f ]; then
    echo "Archive not found: $f. Skipping ... "
    continue
  fi
  mkdir -p $p
  cd $p
  echo "Unzipping takeout-${archiveTimestamp}-$p.tgz ..."
  tar -zxf "takeout-${archiveTimestamp}-$p.tgz"
  echo "DONE unzipping $p"
  cd ..
done

echo "ALL UNZIPPED!"

Why would you need a script (or in your case two) for this? Use brace expansion, cat the TGZs, and extract:
cat takeout-20201023T123551Z-{001..011}.tgz | tar xzivf -

Nice 👍