Steam isn't a platform, its a store. Regardless of how SE treats the steam license, steam is still nothing more than a store page and on their store page it straight up says;
OS: Windows® 8.1 64 bit, Windows® 10 64 bit, Windows® 11 64 bit.
They do not support linux, they are under no obligation to support linux, nor should they support linux. Linux gives users full access to the OS kernal which is just a breeding ground for hacking/exploits and its the very reason developers like Bungie flat out said they will ban anyone trying to play Destiny 2 on Linux.
Using Linux is a "at your own risk" situation. The game does not officially support it and its on you to deal with those consequences, not SE. They have no obligation to abide to a less than 1% crowd that Linux on their home PC's.
