It does not, but Steam isn’t constantly writing to the LEDs. The Customization tab in game mode just lets you pick from the built in hardware effects so it’s not continuously writing. That means it generally is not fighting OpenRGB. The only time it does seem to write to the LEDs repeatedly is during downloads when it uses the LEDs as a progress bar. Also, in desktop mode (on SteamOS or on other distros) it does not seem that Steam touches LEDs at all.