Of course those sizes are without a kernel. Typical everything-included distro kernels are generally a few hundred MiB as they include drivers for everything that might be needed, but a custom build for known hardware can reduce that to just a few MiB.
The ubuntu:24.04 Docker image is only 77.30 MiB.
alpine:3.19.0 is 7.38 MiB.
Of course those sizes are without a kernel. Typical everything-included distro kernels are generally a few hundred MiB as they include drivers for everything that might be needed, but a custom build for known hardware can reduce that to just a few MiB.