Documentation of the API is very terse. It is often a research project to figure it out.
If the API was improved, I feel there would be a lot more community and vendor contribution. Reporting is a huge area where community contribution can help.
MS Graph is fairly good too for documentation, though I found the Webroot API easier to develop against from its documentation.
IT Portal API is reasonible for documentation. Much better than Syncro.
Hudu API is average.
Bit Defender I found quite hard to work with. Similar amount of guess/research work to the Syncro API.
Naverisk has a fully documented API, but the API doesn’t do very much, and its security is poor, even use of the API requires disabling MFA for user accounts Doh!. Syncro API is much larger in scope than the Naverisk API.
RangerMSP API is local LAN only because it is DLL only and has zero authentication. Well structured. Documentation could be better, but a major plus is that it does support proper queries similar to a SQL type language, and the RangerMSP support team provide excellent support for the API.