The server has had to be rebooted several times as kernel update for Linux are an almost daily occurrence. Even Apache was updated suggesting some security or functional issues were fixed.
Linux handles a vast amount of internet infrastructure. The command line interface has very low system requirement for embedded applications. While the laptop used the website has a lot of RAM, Linux can make do with less.
Google and several US corporations all contribute to have developers maintain the kernel and applications. MySQL 8 has been good since the early bugs were eliminated. PHP8 has seen a lot of updates, including several of the components used by WordPress.
Many do not realize that WordPress uses PHP extensively and the extensions are widely used as well. Many other components in the LAMP stack were also replaced. Some less well known parts in the system files for Linux were also updated.
Some of the updates are in preparation for a new certificate from Let’s Encrypt which millions of websites all use.