Just got raspbian installed, uname -a reports kernel 4.19 so, kernel level Steam controller support should be possible. Additionally package "steam-drivers" is in the repository. Problem is, when I try "sudo apt-get install steam-drivers", I get an error message pertaining to Udev rules already set by steamlink.

...probably a work around, just wondering if anyone a little more current on linux than me has thoughts.

BTW - A non-kernel level driver option (that also includes the on screen keyboard) that I've played with in the past is SC-Controller on GitHub. [https://github.com/kozec/sc-controller/releases/tag/v0.4.2] So, if this is not resolvable, there's another way...