I use plenty of apps that start in the background, whose windows I can access via the taskbar and they do not add a window to the desktop on startup. Examples: Backup and Sync from Google, Radeon Settings, Wincompose, Discord... They all have windows I can make appear via their taskbar menus, and yet, they do not do so unprompted on each startup.
This issue appeared before. Although it was marked solved, after windows updated, the problem reappeared.