Solution
Investigating the error message we can discover that the NI Package Manager is reporting an issue finding the 21.1.0 version or greater installation file:
'ni labview-2021 (>=21.1.0)'. The 21.1.0 version in this case is LabVIEW 2021 SP1.
According to the
VeriStand 2021 Readme file, while it recommends the installation of the like-numbered version of LabVIEW in general, it also indicates that certain functionalities require the installation of the LabVIEW 2021 SP1 (64-bit) version specifically.
That said, to resolve this issue, you need to install LabVIEW 2021 SP1 (64-bit) version before installing VeriStand 2021.
Note: VeriStand is only available on 64-bit, like this you need to install LabVIEW 64-bit in every case.