CentOS 7 will not reach EOL until 30 June 2024.
What did end in 2020 for CentOS 7 was "hardware updates", meaning there are no further updates to make CentOS 7 work with new hardware. This is not relevant when using a VPS, because the virtual hardware specification does not change.
CentOS 7 is a current OS, and the use of WHM is fully supported by RedHat and cPanel respectively until the listed EOL. It is stable and well tested, and is currently our recommended solution for running WHM.
Newer versions of CentOS are no longer suitable for use in server scenarios. For this reason, the developers of WHM have added support for a number of additional distributions: AlmaLinux, RockyLinux, and Ubuntu. As these are all relatively new we do not currently recommend any of them, although anecdotally we have plenty of customers who are using these without issue.
In 2023 we will be changing our default installation of "cPanel+WHM" to be based on Ubuntu 22.04 , as by that time we feel that the products in question will have had sufficient time to iron out any issues that are endemic to new releases of software.