again the bound part is your settings being off, if you want full literal control you can set it to set the COM (center of mass) on grip and then you will have really good control over the object. Its disabled by default as generally that is too much control on long weapons for one hand. The long weapons are intentially unwieldy in the template and expected to be used with two hands, the one handed settings are set so that they don’t behave well.
B&S doesn’t lerp afaik, it literally handles mass and COM and constraint settings. the same way, however it has softer constraints (more damping) on the rotation than the linear movements…
Saints and sinners does some actual lerping in that they use an arm IK with a scaler delay input and change that delay, they don’t run things through physics very much at all in that game actually.
If you want to lerp though it is easy enough for you to make a grip script that applies a constant scaler to the motion and place it after the melee script in the list of them, it will set the target transform of the grip to something that you define. You are actually looking at less realistic behaviors like that, but more controllable yes.