Venerable FoTi expounded that it is not about letting go, but non-grasping.
Here is an attempt to loosely translate it.
Letting go is a new invention by modern mankind.
When one attempts to let go, the effort to let go makes the letting go.
Rather, the Buddha taught about non-grasping, which is different from letting go.
Non-grasping is a result of awakening to the nature of five aggregates of clinging.
The realisation that all things are unreal, have no inherent nature, and empty in nature.
You see, modern life and education tells us everything is real. We strive and grasp. That causes suffering.
There is no need to let go. What we need is to watch inwards, like in meditation, and realise the emptiness of things.
Then non-grasping naturally happens.
This is when the suffering will be ceased.
Like mentioned in the Heart Sutra.