But I don’t think it’s realistic to always have the same plugin in the same slot number.
I’ve suggested another solution here.
If Steinberg implements the tabbed plugin windows FR (which they should, as it’s a massive click reducer), Cubase should be able to check if the same plugin as in the currently opened tab also exists in one of the tabs for the next track - then that specific tab/plugin should be opened also for that next track (assuming the option “follow track selection” is active, which should be an option directly on the tabbed window).