I think this is simply an issue with chrome not allowing the GPU updates to display properly. I used the App CpuFloat to measure GPU usage and noticed that scrolling in Google Chrome results in between 10 and 40% GPU usage depending on the page even though it is not correctly displayed by the GPU updated under developer options. Using the CpuFloat tool I noticed that basically anything I do results in GPU usage suggesting that it is already being utilised to at least some degree.Ever wonder why the stock samsung internet browser worked better and smoother than google chrome? Its because google chrome for some reason was set not to use the gpu by default.
You can check by toggling the Show GPU updates in the developer settings. Launch chrome and you will see that only the notification bar is drawn by the gpu. The rest of the app is just being rendered by the cpu.
After so many years since GPU rendering become commonplace I would imagine it would be used wherever possible. I think the Samsung Internet app is simply better optimised to work on Samsung hardware. I have also noticed better overall performance but rely on Google's integration with Chrome on my PC and saved passwords in my Google account.