What is the long-term sustainability story here?

You're deliberately avoiding a network effect lock-in by being federated, you make competition trivial by giving away not only the protocol but also making your code available, and you don't even restrict commercial competition by using the MIT license rather than, say, BSL.

To me that sounds like you are deliberately starting a race-to-the-bottom competition on price with, well, everyone capable of hosting a SaaS? Heck, if you don't end up with some solid competition the whole "federated code" USP doesn't play out. To me that doesn't exactly scream "good return on my €3,8M seed round". Am I missing a brilliant plan here, or should we expect a rug pull a few years down the line?