Those who fear or do not know Kafka are doomed to work around its absence. Like I just cannot understand this mindset of "just educate people" when the system doesn't meet the requirements of its users. If your users want event ordering just give them event ordering.

You can even keep your existing webhook code by providing a synchronous bridge to Kafka so "just send them in order but wait for the 200 before sending the next one." Boom, now you are guaranteed the events are recorded and processed in order.