the Telegram interface can go direct to the database. No "API" as such is needed. Well, the database is the API - via SQL.

Sure - but it's just not a very smart approach to spend time and effort on a single use case, when you could spend exactly the same time and effort (or have people do it for you as a community contribution, like I offered multiple times) on a generic format like JSON.

I don't think you realize just how easy it is to build a bot interface that brings Natural Language Processing (no idea what user interface structure you are asking for. It's all there already) and connectivity to Telegram, Alexa and tons of other messengers out of the box, if only you have a service that speaks a generically understood language such as JSON. That's the only piece here that is missing and that is what I'm arguing for: A PHP page that renders the content into JSON.

I've built a few bots now based on e.g. SAP Conversational AI (which is free to use for non-commercial projects) so I do know a bit what I'm talking about. I'd set up your basic euroga bot in an hour's work and with a few more hours, it could be made really good.