What is Viego's most reliable build when he mainly has to secure the first reset without dying?

The most reliable build on Viego is the one that preserves the first spike while still keeping an escape valve. If your item order prevents you from playing the champion's first real window, the build may look strong on paper but it is not reliable.

When should you truly adapt Viego's build instead of simply pushing entry damage?

You should adapt as soon as the enemy draft stops you from playing the timing the build was meant to serve. If you need to survive longer, absorb more poke, or answer a specific engage pattern, the purchase order must move before you even think about the final six-slot build.

Which enchant should Viego choose when the real problem is mainly surviving until the first possession?

stasis is often the most stable choice because it directly supports this game plan: survive long enough to get resets.

Viego Wild Rift Best Build Guide (Patch 7.2a)

Viego Wild Rift Best Build Guide

Bruiser reset build built around one principle: Viego should not win the fight on the first burst, but survive until the first body becomes available, take possession, then break the fight's tempo open. Early purchases therefore protect access to the reset first, not disguise the champion as a low-margin assassin.