Does Blender have to render videos?

[DeckardX08]

Check if you can disable any unnecessary parts on realtime. Also, any unnecessary modifiers. Armature is slow on highpoly meshes. Subdivision Surface is really slow in general. And if you are Eevee user like myself, it performs about 15% slower if you have normal maps on a mesh with any kind of animated deformation (surface tangents are recalculated in inefficient way). You can use this nodegroup for faster normals:

Way Faster Normal Map Node (for realtime animation playback with tangent space normals)

Something that has been bothering me for a while is the performance during animation playback when using tangent space normal maps. This performance loss only occurs with modifiers that needs to be updated every frame, like the armature modifier usually does. This is due to the tangent space calculation, that happens on the CPU, for every triangle in the mesh. This means that the mesh needs to have its tangents recalculated and uploaded every frame to the GPU, which obliterates performance. I…

Finally, if you have any kind of keyframes on your armature, even if it is just one pose like in your example, Blender will recalculate the mesh on every frame, even if there is just one keyframe