Each Base Unity Callback is executed in a certain order. You can use this official chart bellow to understand in witch order the Callback are executed.
It is important to understand that Unity execute all callback of a categories in a batch at the same time. For example, every Update callback are executed before every LateUpdate.
In Bolt coding as in Unity, you have to understand that every single function/callback is executed on after the other. Unity is “Mono Thread” by design. (You can execute Multi Thread code but it is more complex). So, since every function/callback is executed one by one, nothing is never done at the exact same time, and sometime you can end up with timing issues.
Every OnTrigger and OnCollision callback are executed “before” OnUpdate.