The part that I don't understand about 'fully modular' unikernels, is that you can build a linux kernel with exactly what features you want, but no one does that, so why would they do this?
In comparison, compiling NGINX together with Unikraft results in a kernel size of under 2MB. This means that there is 28MB of kernel we didn't need or want.
[0]: https://arxiv.org/abs/2104.12721 (See Figure 1)