Like za_creature said you can use a language more towards the YOLO end of the spectrum - more Go or Python or JavaScript than assembly or Rust.
Your commit history shows you had an issue of high background CPU use. You probably wouldn't have it in a manually coded implementation.
Why even write one of those? Just set up an nginx proxy cache and call it done.
But that doesn't even scratch the surface of what this project does. We already have a few simple approaches to this problem: apt-cacher and apt-cacher-ng. Neither of which were any help when Canonical was under DDoS. Both of which have proven unreliable.
As I said elsewhere, apt-cacher-ultra is a pretty subtle piece of software, it doesn't just do a naive cache, it fully understands the apt repo structure, validates the repo, and snapshots it, understands what packages your clients frequently request and preemptively downloads updates to them as part of the snapshot promotion, etc. A DDoS of the package sources, even in the middle of an upstream releasing updates, is something a-c-u will handle no problem. I've simulated this by firewall rules blocking upstream traffic. It's also proven much more reliable than apt-cacher-ng.
I've been in the software game ~40 years, I've seen it time and time again: "How hard could it be" and then when you get into it you realize there are a lot of devils in the details.
You might want to change the way you phrase this idea. I think you meant that Go/Python/JS are more "YOLO-friendly languages" (you'll get into far less trouble if you write slop in them). My initial reading was the opposite. It sounded like you were saying the languages themselves are the slapped together garbage.
Assembly is most certainly not "YOLO-friendly", but is more YOLO.