People use the term 'next gen' to describe the PS5 and xbox X and new rtx cards but honestly
it is not 'next gen' until we start having to emulate games from the PS4 and xbox one era. just like ps3 games are being emulated now to be played, because the older consoles are actually too old and discontinued. this is not the case with ps4 or xbox one yet. you can still mostly play what is on the ps5 with a ps4. in fact most of the ps5 games are ps4 games with 60 fps and better graphics, which do not make a game next-gen by themselves. now one could argue that ps5 will be next gen shortly, because ps4 probably has only a short amount of time left before stopping support. but regardless, the ps5 catalogue is still mostly of ps4, so it isn't necessarily old generation games. likewise, it's still possible to run a game released after the rtx 30 series with an older card.
my point is, if the 'older generation' platforms and hardware can still run 'next generation' things, they are not older generation but practically current generation. and that also means that next generation isn't actually next-generation, because there is either nothing or an insufficient amount of exclusive things next-gen. in my opinion, what is truly next-gen is, are the VR games. you literally cannot play them with any older hardware and without the headset and other hardware. and you also cannot play most older games on VR because they didn't account for VR. although the catalogue is relatively small, it's still extremely exclusive and worthy of being called next-gen.