Connect Manager with External Service using API

i am using suiteCRM and Vtiger CRM for my different business and for Accounting we are using Manager server.

I want to access invoices data in CRM (Read Only)
use case: I want to use invoice data to create/update different workflows to handle projects

With API it should be possible as no detailed documentation is available, i am not able to achieve and i dont enough exterpise to do it without help either.

from @dalacor post Real world viability of using an API to connect to Manager - #10 by Davide few years back, i want very similar thing.

with new API version Added new API endpoint and "Access Tokens" screen

it should be possible now but i need support regarding this.
Website i use as bridge bw my other apps (FB, Whatsapp, CRM etc) is MAKE (cannot post link it will treated as spam). they have custom app connection method available.
Screenshots are attached for demonstration.

I have no issue in switching to any other bridging/integration service or website if MANAGER works with that.

If Any can help, please

The manager provides APIs for consumption by other applications.

We can see all the information in baseUrl/api2 and for json data structures we can get it in baseUrl/api. So far I see that api2 is not perfect enough, especially for searches based on field values.

I can’t see where the problem you are facing in consuming web api, maybe you can provide an example or a clearer picture of your problem.

I may not be able to help you, but I’m interested in a discussion about this.