Steam needs the lsb-release package to be installed in order to detect the
distribution name correctly in its "System Information" report. If this package
is not installed, Steam will report a generic "Linux (64-bit)" name.

if you go to https://store.steampowered.com/hwsurvey/, you'll see that the
second most popular distro is the generic "Linux (64-bit)" (although there may
also be some snap/flatpak shenanigans going on here).

Suggestion : make lsb-release a dependency of the steam package.

Steps to reproduce:
open Steam, got to Help->System Information, scroll down to "Operating System
Version"