There are also regular complaints in this forum with problems with the Wordpress plugin
Well, as long as a WordPress plugin exists, it will have support requests with members having certain issues or wanting to do certain stuff that they are not right away able to do out of the box. And in time, such requests must not get lower in number, but must get higher, since it signifies that plugin is being used by a larger user base as time goes on, and also means that new features being added. Reduction in support requests could point to plugin adoption falling or being stagnant or development on the plugin stopping.
Additionally, long-time members must come with increasingly more advanced support requests and issues because it would mean that these members are becoming advanced users and using more of the plugin. Maybe even transforming into addon developers in future.
Regarding current state of the plugin, a large amount of current issues seem to be issues related to handling of different post types during post syncing from Patreon. This feature did not exist in the plugin before May 26, 2020. It was added with supporting text posts only and as time goes on new post types are added. So we are fleshing out a new feature which did not exist. And when a new post type is added at Patreon, it will have to be done again. Something normal for a WP plugin’s lifecycle.
If you have a specific problem that is not related to a yet not-implemented feature, just post a ticket for it so we can look into it. Posting a thread about something that is not supported yet is also welcome since it is an input in respect to feature requests.
As for api being abandoned or not - as development on it is being done, it definitely is not.