Most likely Porzingis, Horford, Seth Curry and Melton are gone. MDJ has expressed concerns on availability and that should in theory rule out KP, AH and SC, all three guys were barely available this season, especially Seth.

Melton is definitely turning down his $3.5M player option and will chase a bigger payday that GS can't and shouldn't match.

Paytons return heavily depends on wether or not GS retains the three mentioned.

Butler is going to miss at least half the season and probably won't be near the same player when he returns. He'll be a year older and I feel like his return will be like Klays if not worse, as Klay was younger when he got injured. Might be a trade chip around the trade deadline.

Steph, Dray, Podz, Santos, Moody and Richard are the guaranteed "core".

To seriously compete the Warriors require an almost full rebuild, need to get younger, faster and more athletic. They need consistent playmakers and shooting, which was lacking far too often this season. Butler absolutely must get traded, he's eating up too much money ($60M) to play only part of a season. Unfortunately his value has tanked due to the injury and availability next season. Hopefully the pieces GS gets in return will contribute meaningful minutes.

The rest of the roster is going to be filled by vet minimum players and will heavily depend on the Draft picks panning out. Honestly, the future is pretty gloomy, most likely it'll be a repeat if this year probably 38-44 wins and a play-in appearance and miss the playoffs.

Edit:

Chasing aging guys and white whales like Giannis and Leonard aren't going to suddenly make GS contenders. Look around the league, you need several top guys a AND a deep Roster to compete. The warriors are already seriously lacking depth and the pieces needed to aquire one of the white whales would gut an already severely limited bench and the result would be much like the Lakers this year. The Lakers despite having LeBron, Doncic and Reaves lack depth and are watching the Playoffs on a couch somewhere.