How soon after a new Pi model comes out do you try? If you wait 6 months then yes, Ubuntu tends to work fine (although you do still need a specific build. You can't just download a generic one).
I used to use Ubuntu MATE on pi, but when the Pi4 came out it took a long time before it was supported.
I tried within a week or two of the cm4 releasing. This may be unfair due to the similarities of the pi4 and the cm4. I’ll know better when pi5 releases. I heavily utilize these in my work, and have great incentive to have new pi’s supported on Ubuntu immediately:)
But it doesn’t surprise me that it just works since Ubuntu is a commercial distro. They even sell products for the Raspberry Pi version.