Announce in June and release in the Fall (not saying this going to happen but I don't see why not), this is going to sell 10+m units not even breaking a sweat and it doesn't matter when they release it or how much lead time is given. I would suspect most of the games will be playable on both the PS4/PS4 Pro/5, meaning you will get downloadable enhancements for the PS5, kind of like Pro patches.
Logically, some of this is based on whether the game is done and PS5 projected launch date, which even they might not even know yet. Either way, Sony needs to get some of these games out over the next 18 months as there is going to be a whole log jam coming - which is not necessarily a bad thing.
Ghost (2020/21)
Death Stranding (2020)
Killzone Next (2020/21)
God of War 2 (2021/22)
Horizon 2 (2021/22)
Uncharted Next by San Diego (2022/23)
Next Naughty Dog IP (2021/22)
Days Gone 2 (if 1 does well) (2021/22) - probably already in pre-production
Japan Studios - over due for something
Spiderman 2 - ?