During Atlassian Unleash, the question was asked how many companies had already adopted microservices or were looking to migrate from monoliths to microservices.
Long-time lurker here. My colleague and I are currently building our own distribution platform, primarily to share access to our software product artifacts (Docker images, ZIP files, MSI packages) to Gumroad subscribers. We are using S3 as a backend, so atleast some of your requirements would be fulfilled. 2FA is on our TBD list.
Totally of topic: I primarily replied because I found your LinkedIn profile, saw "Beaker" as product name for your previous work and laughed hard: We also chose a Muppet name for the platform described above: "Gonzo" ;-)