Yes, remapping of the Bixby button on the Galaxy S8 and S8+ is still totally possible, many may have heard of a update that blocked this but I have my S8+ fully updated and found an app that still allows this function. The app I am referring to is simply called “Bixby Button Remapper” in the PlayStore, and it works quite well allowing you to do nearly anything with this button, for me though I just leave it for the Google Assistant. It’s very easy to setup and has a few different modes, including one with a slight delay on the button which does not use any CPU power, or a mode that is slightly faster but uses some CPU power meaning you’re battery life will be a bit worse and performance could suffer. I recommend just leaving it with the slight delay.
Now go enjoy your new S8s everyone, without having to use the garbage this is Bixby!