TL;DR

v1とv2を両方使い、アップロード、ツイートを行う(らしい)

以下サンプル

import tweepy

# 認証
api_key = ""
api_secret = ""
access_token = ""
access_token_secret = ""

def get_twitter_conn_v1(api_key, api_secret, access_token, access_token_secret) -> tweepy.API:
    """Get twitter conn 1.1"""

    auth = tweepy.OAuth1UserHandler(api_key, api_secret)
    auth.set_access_token(
        access_token,
        access_token_secret,
    )
    return tweepy.API(auth)


def get_twitter_conn_v2(api_key, api_secret, access_token, access_token_secret) -> tweepy.Client:
    """Get twitter conn 2.0"""

    client = tweepy.Client(
        consumer_key=api_key,
        consumer_secret=api_secret,
        access_token=access_token,
        access_token_secret=access_token_secret,
    )

    return client


client_v1 = get_twitter_conn_v1(api_key, api_secret, access_token, access_token_secret)
client_v2 = get_twitter_conn_v2(api_key, api_secret, access_token, access_token_secret)

media_path = r"C:~~.mp4"

media = client_v1.media_upload(filename=media_path, media_category="tweet_video")
media_id = media.media_id

client_v2.create_tweet(text="Tweet text", media_ids=[media_id])

こちら必ず指定してあげてください。

media_category="tweet_video"

誰かのお役に立てれば...

参考