RESTful API JSON SQLite Project

Our need is to connect an accounting program ([login to view URL] in the form of server edition) to a business intelligence platfrom ([login to view URL]). They are both installed on our linux server (Synology NAS) through two distinct Docker sessions and they are accessible only through OpenVPN. Manger is an accounting software which is develiped in .Net (Mono) and it is closed source. It stores its data in sqlite but, as the programmer told many time on the forum, the database is not normalized so if you open the file through a sqlite reader you don't get so much info. Each accounting session is stored in a different database. The data is accessible through two different kinds of REST API (json) with a Basic Authentication session. On the other side we have Metabase which can access different kind of databases (even sqlite but not REST API) to do data analysis. I need a programmer that can create a "wrapper" so that we can query data of Manager through Metabase. Ideally I would think of a PHP wrapper that reads data from the REST API JSON and write it into a normalized database (sqlite or mysql?) but we are open to every kind of solution compatible with our server. Being the first one, in the server edition, fully usable even if not registred and the second one open source the programmer will be able to setup, on his computer, an eviroment to develop everything at zero cost.