Same here. My current method is a self hosted website on my home network which showcases all available games, followed by a bash script download that will automatically generate the yml file for Lutris to fully install any of my 200+ games.
Whilst this is currently the best way I've found for my setup this app seems like the perfect thing to potentially swap to, if Linux was supported.
It looks like you're missing libva.so.1, so go to your /usr/lib32/ directory and make a symlink to libva.so and call it libva.so.1.
However, this probably won't fix the game. I had to also symlink libvpx.so.1 but after all dependencies were met, GlibC throws an error. I think it was due to the version of GlibC used in the game is very outdated and the systems GlibC no longer uses the same calls, so it bugs out. Similar errors are found in the Life is Strange: Before the Storm Feral Launcher, but that can be patched by compiling a simple file, not sure it's possible for this game.
As far as I know the Linux Native version of Saints Row 2 doesn't work.