This honestly sounds like a pretty good idea. Things like ransomware attacks / the fappening / anyone who's had their online banking broken into can tell you that it's not an academic issue. Using Bitwarden so you're not using the same password for multiple places sounds like a wonderful idea (necessary tbh), and adding some stuff to it just so it's not a single point of failure sounds like a sensible additional step that might well have effects in the real world. As others have said in re just adding "google" to the end or something, you don't need to be bulletproof, but you do need to be a hard enough target that the automated / low-effort attacks that definitely will come, won't work on you.
Just remember, this is one of those things where "nothing happens" is the desired outcome. There's a temptation to tell yourself "Well I'm taking these additional steps and it didn't make a difference," but you won't really know if you ever dodge some kind of compromise that would have made a difference -- you'll just have the experience "nothing happened." But that doesn't mean it was a waste of time. Nothing is what you wanted to have happen.