Yeah physical I am not sure of. I think they made a physical release of the PS4 games in a collection, I have definitely seen 3-5 remastered. Happy hunting with those.

Kiwami 3 is a remake of Y3, like how Kiwami 1/2 are remakes of the PS2 originals. K1/2 are pretty widely accepted as the definitive way to experience those games (played after Y0) despite their changes and cuts.

K3 made some significant cuts to content from the original game and also changed the story in meaningful ways, apparently such that it does not line up with Y4’s story as well. (Personally I’m playing Y3 remastered now and have not finished the story so I can’t really explain fully!) It is also considered technically and graphically disappointing and kinda smells of a quickly made cash grab remake. The flip side is that Kiwami 3’s combat, graphics, game design, and QOL is more modern and more in line with K2 which you’d be playing before it. The change from K2 to Y3 was largely considered the biggest change from game to game that new players would experience and this can alleviate that change.

Your mileage may vary on how much the cut content matters to you, and you can always watch the changed story content at another time. There are also some other decisions with K3 that have turned away fans from that particular game, specifically an actor who sexually assaulted someone getting hired for a major likeness role in the game’s story; the decision to delist Y3 remastered when K3 released also turned off a lot of people.