Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
If you are still using CentOS 7.9, it's time to convert to Alma 8 with the free centos2alma tool by Plesk or Plesk Migrator. Please let us know your experiences or concerns in this thread: CentOS2Alma discussion
Another possibility would be to use an external service like blitz.io, stormforger.com or loadstorm.com to generate lots of traffic and concurrent users to your site.
I also use blitz.io, stormforger and loadstorm as Viktor already write. These tools are great for testing professionally from outside. Alternatives are JMeter or BeesWithMachineGuns
The server itself should easily be able to handle this, the question is more how you tune the Webserver and WordPress config. E.g. offloading static content to NGINX and using a WordPress caching solution like WP Rocket or WP Super Cache will increase the max amount of concurrent users. The bottleneck is usually the mysql database. The solution: reduce the amount of calls to the database. Afterwards reduce the amount of PHP processes that have to be started. And so on.
Yes, the server should be capable of doing it. As Jan already said, using internal cache (via a WP plugin) will help your server to handle it. If you want to go a step further, then you should think about a server-side caching mechanism such as Memcached or Varnish.
But you should first try it with the internal solution because this is easier to integrate and to manage.
Change servername to the correct name of your server.
See image for better understanding (hint: the number varies because one more connection was opened during I typed the command):
Regarding blitz.io:
I already asked the support team in January about this issue and they just said that they work on it and it will take some time. If it is still deactivated, then I think that you shouldn't wait for it...