Ordering of analytical events

My team is working on an analytics system for the web app. The web app has a service-oriented architecture, and all events are gathered in one centralized analytics service. The system is sending events from the front-end and back-end; these are requirements of the product team. However, the engineering team has stuck into an ordering issue. For example, we expect that front-end event A must come before the back-end event B, but it does not happen. At the moment, we use client time as the time of the event, but the client’s clock can be completely wrong. There is a plan to avoid that issue by relying on the difference between the client’s event time and the time of the event arrival using the formula:

real event time = analytics service time – (client's event time – event arrival time)

Still, this approach does not provide any guarantees, and we may continue to run into out-of-order events(though a small percentage is expected).

Is it even possible to guarantee the order of events while processing them on the analytics service? If yes, how? Maybe, tradeoffs I mentioned already provide a decent design. What is the state-of-the-art approach to the problem?