I am also having this issue (on Arch Linux). Steam client Jun 4, 2020.
A crude workaround is to disable compositing (thereby disabling transparency), but then you lose all compositing.
If I have Picom/Compton running, the Steam Keyboard on desktop is barely visible on top of light backgrounds.

I also ran into this issue on Ubuntu 20.04.
same problem with ubuntu 20.04 , its too transparent on the desktop on bigpicture is fine.
We all got Nvidia cards? Tried on my laptop that has Intel integrated graphics running the same software versions as my desktop in the first post and it's working properly.
I can't seem to be able to repro this on Mesa either.
Hello, per "Fixed a regression with transparent visual selection for SteamOS overlays and on-screen keyboard causing invalid rendering on NVIDIA configurations" in the 2020-08-05 steam client beta update, please opt into Steam's beta client and retest.
It's now back to being opaque; thanks for getting that patched up!
yes its fixed now thanks a lot, now I can use steam desktop mode on my steam link!
Hi,
I'm running the same issue with Steam on ubuntu 20.04 64-bit, with NVIDIA (440.100).
It seems the patch has been tested.
I don't really know about steam calendar updates, does someone know when it should arrive for the non beta version of steam ?
thank you anyway, i will wait, looking forward to re use the OSK :)
Nothing extracted yet.
Your system information
Please describe your issue in as much detail as possible:
When using the on screen keyboard with the Steam Controller, the keyboard's opacity is very low. It's impossible to use on bright or mixed screens. If you can get a black surface behind it, it looks normal though. No issues within Big Picture Mode.
Steps for reproducing this issue: