What is Olaf's most reliable build when he mainly has to make the run into contact profitable?

The most reliable build on Olaf 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 Olaf's build instead of simply pushing his stat-check profile?

Loses value against heavy kiting, sustained poke or high burst before sustain kicks in.

Which enchant should Olaf choose when the real problem is mainly lasting through the whole ultimate?

glorious is often the most stable choice because it directly supports this game plan: enter fights uncontested, absorb initial burst and convert the fight into a favorable extended duel.

Olaf Wild Rift Best Build Guide (Patch 7.2a)

Olaf wins through duration, not burst. This build maximizes his uptime in fights: armor shred for tank relevance, sustain to survive focus, and durability to outlast opponents.