This article has a useful guide to disabling bixby.
Disable Bixby Voice
Go to Bixby home. Click the three vertical dots then settings. Uncheck Bixby Voice
Disable Bixby Button
Go to Bixby home. Click the cog. Uncheck Bixby Key
Remove Bixby from Home screen
From home screen, hold down on empty space. Swipe right until you see Bixby home screen. Uncheck Bixby ...
You can disable the Bixby button by using
Bixbi Button Remapper - bxActions. This allows you to remap the button to another action.
As for disabling Bixby altogether, I am unsure of how to do it. There were mentions of using Package Disabler Pro+(Paid app) to disable it. I do not know if this will work, but people keep recommending it.
Another mention ...
Yes this can done. I recently updated guide to remove Bixby using adb.
Assuming you've adb installed on your machine, you can run following command to get packages related to Bixby.
adb shell pm list packages | findstr "bixby"
Next step is to uninstall those packages for the current user (that is you). An example for one of the packages:
adb shell pm ...