Currently, ChromeBinariesProvider, FirefoxBinariesProvider and EdgeBinariesProvider only provide binaries for installed stable versions of the browsers. In addition, It is not possible to configure usage of pre-release browser versions on a configuration/build configuration level (e.g. WebTestSection and Remotion.Build).
This could be implemented by 1) adding new SupportedBrowsers to the project (e.g. ChromeCanary, ChromeBeta etc), 2) configuring builds that use these browsers, 3) adjusting the WebTestSection entries to allow these pre-release versions 4) adjust the BinariesProviders to download the corresponding drivers and provide paths to the installed prerelease binaries. Every pre-release browser version should be able to use virtually all of the infrastructure of the stable version. In theory, merely the binary location is different.
These steps are just a suggestion that seem sensible to be at the time of writing.