The sentry/sentry/src/Transport/HttpTransport.php:81 will not send events while running in a worker process. Switching the statement to $promise = $this->httpClient->sendRequest($request); will work.
One can also observer how the $this->pendingRequests[] is holding all the pending request. But non is getting send to the sentry server for display in the sentry frontend.

Can You please advice how to continue?