Migration

Each guide maps one library’s API to Onity, names the behaviors that differ, and lists what Onity does not ship so you do not look for it.

From Zenject: bindings, injection, factories, lifecycle, scopes, signals.
From VContainer: registration, lifetimes, entry points, async startup.
From R3 and UniRx: primitives, operators, lifetime, what is not shipped.
From UniTask: name mapping, behavior differences, 0.5 to 0.6 notes.
From MessagePipe: the Migrating from MessagePipe section of the Events and Messaging guide, and the Messaging vs MessagePipe comparison.

Method

Replace one library at a time. Finish the DI move before the reactive move, and the reactive move before the async move; the mapping tables assume the earlier pillar is already on Onity.
Keep the old library only inside the bounded context that still depends on it. Do not add adapters that bridge the two libraries across the whole project; convert one scene or feature, verify it, then move to the next.
Verify every name against the installed source under Packages/com.onity.framework/Runtime/. The tables are checked against Onity 0.8.2; an API that is not in a table does not exist in Onity, and a Zenject, VContainer, R3, UniRx, UniTask or MessagePipe analogy is not evidence that it does.
Read Lifecycle and Scopes before you move async startup code. The scope token and IOnityAsyncInitializable replace most hand-written startup ordering.