Problems with moving objects

Hello, whenever I highlight some part of an object and move it, it moves the whole object. I am trying to move the highlighted part.

You may have proportional editing turned on:

https://docs.blender.org/manual/en/2.93/editors/3dview/controls/proportional_editing.html

Edit

Maybe related:

press o (ooh) then try again see if that works, it’s releated to @RandomPanda answer