When and in what order do user startup items execute?

from say shell:startup (%userprofile%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup)
there are a number of
shortcuts
executable files
cmd (batch files)
.ps1 PowerShell files

On identical workstations (not in a AD domain), they seem to execute in a different order
Without going to the effort of having a single script that executes everything in the correct order, is there a config, registry key etc that can be changed?

An additional problem is users add their own items to shell:startup

I was always of the impression it was based on the CPU load at startup and how long it takes for the individual items to load.
Now, whether items fight for a position, I couldn't tell you!
There's probably a way to regulate it through Task Scheduler.

Right after logon, the registry Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\StartupApproved\Run key is read. It might be worth checking the order on the various systems.
But I think @Edwin is correct as the OS would logically prioritize based on CPU load.
Whether or not that is the case, only tools like AutoRuns/AutoRunsc & AdvancedRun would let you see that.
One could always use task scheduler and specify a dependency on the previously 'run at login' instance and control it that way.

Whatever you do about this topic, do make sure you check the All users startup as well as the Current user startup that you mentioned.

Start-up - All users
C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup

Start-up - CurrentUser
%UserProfile%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup
=
C:\Users\%UserName%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup


All the best,
Denis

When I was using Windows 7, I used a program to control the order and timing of the startup programs. It even showed the startup times for each program. I forget the name of the program but I did find these options. If you do decide to try any of them I recommend you make a backup image first. 7 Free Software To Delay / Disable Startup Programs And Boost Windows Boot Up Time and 14 Best Startup Managers for Windows 10/11 [Updated List]