Webhook response timeout and queue handling for Salesforce CRM REST API syncs

Hello Salesforce Developer Community,

We are optimizing background listener stability and webhook handling when syncing lead payloads into Salesforce CRM endpoints.

Technical Setup:

• Our integration layer at Frontline Sales Consultancy (flsc.co.uk) triggers automated sales notifications and syncs inbound lead pipelines via Salesforce REST Webhooks.
• Listener sockets are configured using TLS 1.3 encryption over secure HTTPS.

The Issue:

1. Under high concurrent transaction spikes, external POST webhook listeners occasionally hit HTTP 504 gateway timeout thresholds before acknowledging payload completion.
2. Direct REST API calls to the org endpoints resolve normally under 150ms.
3. Are there recommended Apex asynchronous queueable job patterns or buffer queue settings to optimize inbound payload ingestion without dropping connection sockets?

Any advice on managing high-volume asynchronous API triggers would be appreciated!

Thanks!