5. It looks like you delete the existing installation before attempting to download the new version. If the new version fails to download then you are left without a working installation.

6. You don't need to run pwsh.exe to get the version.

PS> (Get-ChildItem 'C:\Program Files\PowerShell\7\pwsh.exe').VersionInfo

ProductVersion   FileVersion      FileName
--------------   -----------      --------
7.4.5 SHA: 68... 7.4.5.500        C:\Program Files\PowerShell\7\pwsh.exe

7. I am missing something here.

if ($PSVersionTable.PSVersion.Major -lt 7 -and $env:PSExecutionPolicyPreference -ne "Bypass") {
    Start-Process powershell.exe -ArgumentList "-NoProfile -ExecutionPolicy Bypass -File `"$PSCommandPath`"" -Verb RunAs -Wait
    exit
}

If the script is running then it must already have had a policy that allows the script to execute.

FYI @91ajames there is already a somewhat maintained install-powershell.ps1 script that you could make use of or be inspired by.

There are some PR's that are outstanding to add in some features to this script in the PowerShell repo but it's not a high priority for the team to keep maintaining.

Also Windows 11 also has the winget tool as part of it and that allows you to install silently too with winget install --id Microsoft.PowerShell --silent

(I don't want to discourage you from sharing stuff, but please think of the audience, or what you would/wouldn't want from a third party script geared toward "IT departments, system imaging, automated deployments, or lab setups", and what it would do without telling you and/or isn't documented.

I trust the script meets your needs, but it's a pretty specific use case with many assumptions about environment. (And if it's a fresh OOBE install, how/why would there be existing installs to clear out?)

• I, as an admin, would be very upset to run a "Install Powershell" scripts to find existing modules were deleted.
• You have a comment for one step that says "optional", but there's no conditional logic.
• The clearing of all functions and variables at the end is peculiar, may have unintended consequences.

Bonus suggestion: Since you're obviously targeting/assuming Windows, use Start-BitsTransfer instead of invoke-webrequest, it's much faster.