There is no way to disable caching. Data is saved right away, but it's not refreshed until you can relevant API to change something.
I wonder if there’s a way to make the UI update from a external trigger or from a database update. Is it possible?
Unfortunately it's not possible at the moment.
Do you have any recommendation on how could I share data with others systems or others instances of Traccar?
Other systems - database or data forwarding. Traccar - forwarding (but it's limited).
One more question: is there any documentation where I can get started with data forwarding?
Yes, there is documentation. Please use search before asking questions.
I’ve two instances of Traccar that are pointing to the same database but they don’t seem to stay in sync. Apparently, some of the information about the devices, like connection status, are kept in memory (I believe for performance reasons) and not saved to the database right away. Is it possible to disable this caching and only use the database?
I’ve looked into the documentation but didn’t find anything about a caching configuration.