There is coincidentally an article on this topic on the front page - https://www.rdr2.org/news/far-cry-5-compete-red-dead-redemption-2-year/
I don't think that Rockstar would be concerned with Ubisoft/Far Cry in the slightest. Sure, FC is a popular series, but it is NOTHING compared to Red Dead. If anything Ubisoft are probably holding off announcing anything about their new game (and maybe even delaying it) until RDR2 has been released for a while... Otherwise they might try and announce and release it before RDR2 is launched, particularly if there is a delay.