I'll likely get one eventually no matter what (I waited to get my PS5 in 2023 and got it for $250 used after all) but if they wanted me to get one on day one, they'd have to have some big, interesting new IP in the launch window. Maybe something big from Team Asobi or some new studio. I tend to miss Sony Japan's output so maybe something that is distinctly Japanese. As far as existing IP go, Ape Escape 4, a new Twisted Metal, a Legend of Dragoon remake or a new LittleBigPlanet would be extremely tempting.
I'd also need it to cost like $500-600. We're reaching this point where if you're a still a 1080p gamer like me, building PCs that can decently handle 1080p gaming with some level of futureproof status is rapidly getting cheaper. I don't care how well the next-gen console pushes 4k considering we are currently in an era of AI upscaling and frame generation that makes games look and feel worse most of the time anyways. Either give me a super compelling 1080p experience in the form of 120fps modes as more of a standard or at least be affordable enough that it competes with my want to just upgrade my PC.
For something more outlandish, disc-based PS3 backwards compatibility would get me purely for the convenience of it all, though I'd still probably use the PS3 itself more for that purpose.
I'll be honest though, while I don't have my PS5 I stopped being a giant Sony fan starting with the PS4. Around 2016/2017 was when that company lost a ton of goodwill with me as they pretty much completely abandoned what made the PlayStation brand so exciting. All their games play and end up structured the same, they focus way too hard on AAAA style games that take 4-5 years to make instead of having a more diverse portfolio in terms of genre and budget. Non-Nintendo consoles in general are becoming less and less compelling as exclusives continue to become less and less relevant. The convenience and value proposition that used to be the backbone of consoles is mattering less and less as time goes on so idk if in 2-3 years Sony will really be able to sell me on something I care about.
Fuck raytracing, I hate how most raytraced games look and I hate how much about modern AAA presentation is just using stuff to bruteforce realism and remove so much of the character and artistry from visuals. Uncharted 4 was pretty much the last time I think a game's raw fidelity was able to truly wow me, ever since then it has felt like immense amounts of wasted time and effort all to make games look more generic and run worse. Wahoo.