I don’t know if this will help you, but I wrote a tutorial on how to setup a local registry on the LAN on a Fedora Server or RHEL-compatible server. https://techne.hyperreal.coffee/tutorials/setup-a-lan-container-registry-with-podman-and-self-signed-certs/

But anyway, it’s unlikely docker.io or quay.io or ghcr.io will go completely offline. If anything they might experience a DDoS, in which case I imagine they have competent devops employees who would ensure they become functional again within a matter of hours.

I self host my own website, blog, and a dozen privacy-friendly alternatives and front-ends to various web sites. I use a dedicated remote server for this, so nothing is on my own bare metal. netcup.de has a variety of VPS options that give you good hardware resources for your money. You can get a VPS with 8 GB of RAM, 4 core CPU, 256 GB disk, and 2.5Gbps network throughput for $6.33 a month (not including initial setup cost). Compared to what Vultr and Akamai offer for the same price, this is a steal. The company is based in Germany, so you have to convert the euro prices to US dollars if you’re in the US. The only thing about netcup.de is that your options for the location of your server are limited. They have one US location and the rest are in Europe. This is not a dealbreaker for me, though. And they guarantee 99% uptime. I’m pleased with their service. If you just want to host your personal services on a more long term basis and don’t care about scaling and deployment turnover, then netcup is great. Akamai, Digital Ocean, and Vultr are more for short term disposable, scalable VPSes or web apps and they have excellent data center availability.