#embed should make it fairly easy to write an installer from scratch. You'll still have to handle things like registry keys on Windows manually, but the barrier to entry for developing installers will be much lower.
At least on Windows you could already do that with resource files, even if not as easy as #embed.
And although even Microsoft teams themselves aren't that great following their employers advice, the use of the registry should be minimized to the keys that are really required by the system, everything else should be in manifest files, or local configuration.
Depending on how much you would like to depend on MSI, MSIX, or do your own thing, running a .reg script might also do the job if the entries are rather simple.
