Telegram? WhatsApp?

ANSWER

TikTok. The Chinese social media app for sharing short videos was the most downloaded app in 2021 and remained in first place in the first three months of this year, followed by Instagram. By store, TikTok ranks first in the App Store, followed by YouTube, while on Google Play, Instagram is the most downloaded app, followed by Facebook. 

Here you can see the list of the top ten downloads, according to VisualCapitalist.