Looks like TikTok is not the right social media to promote cryptocurrency and maybe the Doge coin trend in TikTok is only temporary. That was done just for fun and to follow the existing trends, Twitter and telegram are still a suitable place for that.
TikTok is a small app for making Video's but it is not tool for promoting cryptocurrency, you are right, as of now, Twitter and telegram are the best choice for promoting the cryptocurrency. Doge coin created some Hype through the Tiktok but it is not the tool to increase the coin price.