Briefly informed: Microsoft always provides test versions for Windows 11, Windows 10, Server 2022 or 2019 via the Microsoft Evaluation Center. This page is currently unavailable. There is now a replacement page for this, with all the links.
The trial versions for Windows 11 and 10 is the Enterprise (LTSC) and can be used for 90 days. The two server versions each 180 days. These are activated for the period and can be fully used. Is ever interesting to maybe test something in a VM. In addition, there are already full VMs for VMWare, Hyper-V, Virtualbox or Parallels. These are currently valid until 10.07. usable.
If you need a 90 / 180-day version, you can find it on the tech communitypage of Microsoft. If you are looking for the normal ISOs, you will find them on these pages, as always