WP-Cron events and cURL error 28

Since the last WordPress release 5.9.2, I got the critical error from the Health Site inspection :
API REST request failed due to error
Error : cURL error 28: Connection timed out after 10000 milliseconds (http_request_failed)

The WP-Cron was not working any more and all event requests were blocked. In order to unlock the events, I had to resort to the alternate job scheduling method by adding
define(‘ALTERNATE_WP_CRON’,true); to the wp-config.php file.
However the cURL error 28 remained.
I followed then the usual suggestions (for example : https://ertano.com/curl-error-28-connection-timed-out/):
1. I checked that there was neither firewall nor security plugin.
2. I desactivated all plugins, but the error was still there
3. I checked that the HTTPS/SSL was properly working
4. I had a look at the software installed at my server host : PHP (7.4.25) cURL (7.64) OpenSSL (1.1.1)
But it seems that the cURL library version (7.64) is outdated, since the last version is 7.74.
Have you an idea ? What is the cURL version generally used ?