Seems to me like you have an opportunity to develop a couple SDKs in your customers' favorite languages (probably python and typescript) and a simple "Get Started" template that could alleviate a lot of these requests. Show them the base case, let them figure out how to work with your api via an SDK instead of directly with an API and let the advanced users build their own SDKs in whatever language they prefer. Since its, as OP claims, a simple HTTP API, the SDK could be generated with OpenAPI client generation tools.
And then the customers will open support requests for code generated by an AI that misuse that very SDK. It doesn't look like OP's issue is with the code per say, only with the lack of skills of its customers, regardless of the code they write...
At the very least, GitHub Copilot will have an easier time with an SDK loaded into context than an API documented only on the web. If the customers are using typescript then they'll have some red squiggles that at least some of these people will bother to read prior to asking for help. The uninformed consumer of OPs API will probably be more comfortable to work with an SDK instead of writing their own clients.
The way I see it is that OP can either complain about customers being annoying, which will happen whether or not OP does anything about his problem, or OP could proactively produce something to make their product better for the demographic they're targeting. At this point it's pretty clear that the users would rather be helped than help themselves, so meeting them where they're at is going to be more productive than trying to educate them on why they suck at both coding and asking for help (or free work).
I don't really know how to point this out without sounding rude and obnoxious, which is not my intention, but it's "per se" (Latin for by itself), not "per say".
Maintaining an OpenAPI spec when you make changes to your API and regenerating the client SDKs through CI is really not a ton of extra work. A template to show a dead simple usage of your API can pay dividends as it lowers the barrier to a customer adopting your product over a competitor's.
