Authorise my iPhone SE 2020 to see it among devices in iTunes for Windows
Logging-in to the same Apple account / using the same Apple ID on both iPhone and PC isn't enough to enable sync between these two devices.
In addition, it is also needed to physically connect iPhone to a PC (in this case) for the first time.
Only then iTunes for Windows 10 will:

recognise device and ask to add it to iTunes library for given Apple ID,
configure both device and iTunes on PC and
perform initial data and files sync.

Only after then given mobile device will appear in File &gt; Device menu with its unique name next to Sync in a corresponding menu item.
Some details may be found at Apple Support site in this article.