Electronic Arts and Respawn Entertainment have teamed up to create the popular Battle RoyaleApex Legends” will no longer be playable on Linux.
Linux was exploited to prevent cheating
This response was taken as part of our anti-cheat measures. As the development team continued to investigate, it became clear that Linux was a conduit for various cheats and exploits (attacks that exploit system flaws).
Linux is characterized by being an open source OS, but cheating via Linux is difficult to detect, which is an attractive point for cheaters and cheat tool developers. Although there are a small number of healthy users who will be affected by this decision, the decision to block it was made because continuing to distribute it on Linux could affect more users.

In addition, you will not be able to play on Steam Deck that uses Linux-based SteamOS. It is said that it is currently difficult to distinguish between SteamOS and Linux, so they had no choice but to block it. If you want to play on a handheld device such as Steam Deck, you can do so by installing Windows.
Users are complaining about this decision in X's replies. There seems to be a fair number of people who don't like the decision, such as those who are disappointed that regular users of Linux and Steam Deck, which require less effort, have chosen the method that costs them money, and those who are asking for a refund for skins.

It is currently unknown whether measures will be taken to make Apex Legends playable on Linux in the future. If you were playing on Steam Deck, consider installing Windows or switching to another handheld PC.