こちらのプログラムを Botocore で書いてみました。
Python3: AWS IOT の Device Shadow

エンドポイントは次のコマンドで調べます。

aws iot describe-endpoint --endpoint-type iot:Data-ATS

エンドポイントが次の場合のサンプルです。

https://abcd6goq68zt4o-ats.iot.ap-northeast-1.amazonaws.com

もの

sample_sep26

デバイスの状態が OFF であることを通知

report_off_thing.py

# ! /usr/bin/python3
# coding: utf-8
#
#	report_off_thing.py
#
#					Sep/29/2021
# ------------------------------------------------------------------
import json
import botocore.session

# ------------------------------------------------------------------
url='https://abcd6goq68zt4o-ats.iot.ap-northeast-1.amazonaws.com'
thing='sample_sep26'
#
# iot_data = boto3.client('iot-data', endpoint_url=url)
session = botocore.session.get_session()
client = session.create_client('iot-data', endpoint_url=url)

shadowDoc = {'state':{'reported':{'led':'off'}}}
payload = json.dumps(shadowDoc)

res = client.update_thing_shadow(thingName=thing, payload=payload)
#
# ------------------------------------------------------------------

デバイスの状態が ON であることを通知

report_on_thing.py

# ! /usr/bin/python3
# coding: utf-8
#
#	report_off_thing.py
#
#					Sep/29/2021
# ------------------------------------------------------------------
import sys
import json
import botocore.session
# ------------------------------------------------------------------
url='https://abcd6goq68zt4o-ats.iot.ap-northeast-1.amazonaws.com'
thing='sample_sep26'
#
session = botocore.session.get_session()
client = session.create_client('iot-data', endpoint_url=url)

shadowDoc = {'state':{'reported':{'led':'on'}}}
payload = json.dumps(shadowDoc)

res = client.update_thing_shadow(thingName=thing, payload=payload)
#
# ------------------------------------------------------------------

デバイスを OFF にするように指令

command_off_thing.py

# ! /usr/bin/python3
# coding: utf-8
#
#	command_off_thing.py
#
#					Sep/29/2021
# ------------------------------------------------------------------
import sys
import json
import botocore.session

# ------------------------------------------------------------------
url='https://abcd6goq68zt4o-ats.iot.ap-northeast-1.amazonaws.com'
thing='sample_sep26'
#
session = botocore.session.get_session()
client = session.create_client('iot-data', endpoint_url=url)

shadowDoc = {'state':{'desired':{'led':'off'}}}
payload = json.dumps(shadowDoc)

res = client.update_thing_shadow(thingName=thing, payload=payload)
#
# ------------------------------------------------------------------

デバイスを ON にするように指令

command_on_thing.py

# ! /usr/bin/python3
# coding: utf-8
#
#	command_on_thing.py
#
#					Sep/29/2021
# ------------------------------------------------------------------
import json
import botocore.session

# ------------------------------------------------------------------
url='https://abcd6goq68zt4o-ats.iot.ap-northeast-1.amazonaws.com'
thing='sample_sep26'
#
session = botocore.session.get_session()
client = session.create_client('iot-data', endpoint_url=url)

shadowDoc = {'state':{'desired':{'led':'on'}}}
payload = json.dumps(shadowDoc)

res = client.update_thing_shadow(thingName=thing, payload=payload)
#
# ------------------------------------------------------------------

Shadow の状態を取得

get_thing_shadow.py

# ! /usr/bin/python3
# coding: utf-8
#
#	get_thing_shadow.py
#
#					Sep/28/2021
# ------------------------------------------------------------------
import json
import botocore.session

# ------------------------------------------------------------------
url='https://abcd6goq68zt4o-ats.iot.ap-northeast-1.amazonaws.com'
thing='sample_sep26'
#
session = botocore.session.get_session()
client = session.create_client('iot-data', endpoint_url=url)
res = client.get_thing_shadow(thingName=thing)

bb=res['payload'].read()
print(bb.decode())
# ------------------------------------------------------------------