How should I go about making a tweened spinning model?

I am trying to make a model spin in 360° using one tween. My issue is that everything that I have looked up or tried has had me not use a tween or have me use around three tweens. I have tried to look for solutions but I have found none so far. Is there anyone out there who knows how to do this correctly?

One neat way of doing this is to unanchor everything in a model except the primary (center) part. Afterwards, you weld with WeldConstraints all unanchored parts to this root and tween it.