I came up with the main concept:
Сreate icons for major world holidays - similar to the largest marketplaces, which change the image of their application for events (leaving the base logo dominant for recognition)
The main idea behind the concept is that users can customize their icons depending on the period. For example, on a holiday, time of year for a certain period. Also, the Telegram administration, according to certain rules or parameters, can do this independently, as marketplaces already do.

It looks neat, although it feels a lack of contrast. It's hard to recognize Telegram logo from a small image