Is Windows 11 IoT a functional equivalent to the "real" Windows 11 for a PC?
It very much is, it just doesn't have the microsoft store installed by default.
And the LTSC version won't keep trying to upgrade itself. LTSC enterprise version of Windows or bust.
Yes Store and everything
If you have to use windows W11 IoT is the best version of windows to use. Zero bloatware. Only downside is you can't update an existing machine to it you need to clean install.