Is there any way to prevent this by locking the folder order or disabling this function?

No.

Have you considered adjusting the sensitivity of your mouse / track-pad in the operating system?

I have the same issue. It's nothing to do with mouse sensitivity. The problem usually occurs if the cursor freezes for a second as often happens when spinning up a hard drive. This means you lose track of where it is and you can end up moving a folder unintentionally. It's far worse on smaller devices which is why I don't use Thunderbird anywhere except on a desktop.

A simple global lock is all that's required. Doesn't need to be complicated. It's pretty rare to need to move folders around so no need for a quick way to do it anyway.

The following add-on might be helpful: Disable DragAndDrop (New) https://addons.thunderbird.net/en-US/thunderbird/addon/disable-draganddrop-tb-v2/

Quotation from the above link:

Disable drag and drop on the folder tree in order to prevent unintended folder movement.