i think you might be misunderstanding what ‘3rd party’ means. if ubisoft is making you use an ubisoft launcher to run ubisoft games, that’d be first party. here’s an article detailing what the terms mean with regards to game developers. a third party launcher would be like when you add a non-steam game to steam.
i think they know that. if you pluralized ‘sclerosis’, you’d expect to get ‘scleroses’. just like pluralizing ‘thrombosis’ gets you ‘thromboses’.