Would oil denial keep Yamato in home waters?

If Japan failed to capture Dutch East Indies oil, would Yamato stay near the home islands?

Probably yes; oil scarcity would sharply constrain major fleet movements, while submarines from Singapore could further isolate Japanese-held territory.

Without Dutch East Indies oil, Yamato and other large warships would probably remain in home waters. Their fuel consumption would make major movements harder as stocks contracted. Allied submarines operating from Singapore could threaten routes to the Philippines and make captured territory increasingly difficult to sustain. In a later stage, carrier cover might even make surface convoys to China possible. That remains a more distant consequence of retaining Singapore and restricting Japanese fleet movements.