There's a few games that I think people aren't too aware of and should definitely peep. They're the closest and most identical games we have to others like jak and ratchet. There isn't one for sly cooper but I'm sure there'll be one or two at some point.
So, a few of the games in a row:
Skylar & Plux: Adventure On Clover Island
While skylar and plux/geargrit are both shockingly similar to jak 1 & 2, akimbot doesn't outright scream ratchet and clank but it's the closest thing we have to that series. I've played all 3 and I'd have to say that they're worth looking into.
As far as I know, skylar and plux was a prototype for a bigger game which explains why it's pretty short. It has somewhat of the same atmosphere and landscape detail that you'd find in jak 1 along with a little of the same mechanics.
Geargrit, as it's still being developed at this moment, is probably the jak 2 of this age. Same gritty tone but less of an open world game. It has GTA aspects whereas you can steal vehicles and kill civilians. It'll have newer elements that you wouldn't really find in jak 2. Things like a kick that'll launch you upwards or forward, a more developed combat system and a ultimate(not exactly a dark form trigger like jak, just a stronger attack).
akimbot, while being a much lesser ratchet and clank, is still worth checking out. in my opinion, it's pretty ok. I'm not exactly the biggest fan of it but I still want to recommend it regardless because there aren't many devs out there who're making similar games close to ratchet.
geargrit and akimbot are on steam but skylar and plux is unfortunately delisted. It's still playable tho, you can find it on the archive.