You can’t really distinguish distinct stylistic periods anymore, at least not since 2015ish.
Games absolutely have stagnated and gameplay youd see in a 2015 game does not differ much from current day games.
This is in stark contrast to a game from 2005 and 2015 within the same genre.
There aren’t that many outdated/antiquated features and gameplay quirks anymore, the devs outside of sports games -for better or for worse- all coalesced into some form of either cinematic third person game, CoD/battlefield style first person shooter, retro-throughback-but not really shooter, or souls likes and all with light to medium rpg mechanics.
What this means that a 2015 game -while 10 years old, older than the PS1 was when the PS2 released- doesn’t feel old and can’t really be classified as such without redefining the term to just mean age.