Golden State is prepared offer James the $15 million Non-Taxpayer Mid-Level Exception this summer. That would involve the Warriors clearing some room under the first apron, as using the Non-Taxpayer MLE triggers a first-apron hard cap. However, Golden State is confident that they can create the room necessary to use the full exception.
The Warriors plan to clear additional spending power seems to revolve around Draymond Green opting out but re-signing on a new deal that lowers his salary for this season. It's important to note that Green and James share Klutch Sports as their agency.
Even with the age of the roster and their stars too, I do think Lebron's best bet is Golden State. Weird to say with a Lakers team with Doncic, but GSW has Curry, Butler, Green (presumably lower salary), probably Porzingis or Horford, and still some solid role players in Gary Payton II, Santos, etc. It's a high risk-kind of move but they would still have more high-end talent than LAL. Injuries really sabotaged Golden State last year otherwise many still predicted they'd make the playoffs outright (no play-in). Butler as a 3rd option is a lot better then Reaves.