Just last month the first Redmi phone with a high refresh rate screen came out, the Redmi K30 and its 5G variant had 120Hz IPS LCD panels. That may not be the best that the K30 can do - Xiaomi VP Lu Weibing posted a video of the Redmi K30 5G screen running at 144Hz. The VP says that this was a test in the laboratory and did not specify whether the company will release an official update that will push the screen to the higher refresh rate. The hardware is clearly capable of running at 144Hz, but there are other considerations - e.g. there's a community-made mod for the Redmi K20...
Source: https://www.gsmarena.com/xiaomi_demoes_a_144hz_mode_for_the_redmi_k30_5g-news-41006.php
