Delayed response of mesh to armature deformation

Please help


I'm using Blender 2.83

Kindly see the video of my character, there we can see a lag, which is really a horrible mess while animating. I may have made some mistake while  making the rig from single bone. But I have checked again and again but could not identify any parenting issue or the like.

I had seen in earlier versions of Blender in relations tab, "update" option for the mesh, to update the motion of the rig as and when deformation happens.

Kindly guide me, what could be wrong with my rig, or how such delay/lag in mesh response be treated.