I've also done plenty of SOAP back in the day. I independently invented the equivalent of SOAP in an API back in 1998 where my RPC API used only one method, which was basically a "call(command)" for sending XML data upstream and getting an XML response (C++ app). The request XML had the "name" of the "verb" as part of the request. Basically a "command pattern".

So what I do today is I use "REST APIs" (like in Java Spring, Axios/Ajax, etc.) but all my endpoints are named as "verbs" (not nouns), and the only HTTP verb I ever do is a "POST".

So everything boils down to this:

let myJsonReponse = api.doSomeVerb(myJsonRequest);