TLDR:

(Article from 2017)

The Tizen community was shaken last month by a Kaspersky Lab Security Analyst Summit presentation by security researcher Amihai Neiderman that claimed that Tizen was full of security flaws, including 40 previously unknown zero-day vulnerabilities. “It may be the worst code I’ve ever seen,” Neiderman told Motherboard. “Everything you can do wrong there, they do it.” (source)

(Wiki article)

On December 31, 2021, the Tizen app store permanently closed.[22] The last smartphone based on the Tizen operating system is the Samsung Z4 which was released in 2017.