I’m not very well-versed into all of this, but if what you’re referring to is technically known as Unified Kernel Image, then you should know that unfortunately it’s currently not supported on systems that rely on ostree; thus unsupported on Silverblue. A lot of work has been gone into this over the last year, but I’m afraid we’re still (at least) two major releases removed from proper UKI support. For regular Fedora, consider referring to this excellent guide.