Required Software Architecture & Design freelancer for Help in designing the high-level architecture of a software module job

I need help in the design of an object.

The object is a list of records.
Records can be added, removed or modified by clients (using a Web API or another means).
The clients should be notified of any new update to Refresh their interface (Listeners?)
Some concurrency handling is needed.
1-If an Item is deleted by client A, and shortly afterwards client B tries to modify it, nothing should happen
2-Ideally, an action should be refused if the timestamp of its record is earlier to the record current timestamp on the server.

Also, I need the object status to be persisted in a database, so that is a crash happens the system can reinitialize its state.
Actually, I don't need the object in memory, but I am not sure if using database triggers is appropriate in such case.

Skills & Expertise Required

Software Architecture & Design