Jonathan is very knowledgeable and is usually right. But in this specific instance, everything points out that this is indeed a component of a rocket.
The eyewitnesses describe that the object fell with a high velocity, with a loud noise, and was hot when it landed.
The better angles in the video [1] show molten metal on the outside, and a typical aerospace bolt pattern with carefully machined pockets around the bolts.
This kind of construction is typical in rockets, for example at the top and the bottom flanges of some stages of the Indian PSLV rocket [2]
There are lots of videos of similar Thai fireworks, but I think is the largest one I've seen. Also, based on my amateur rocketry experience, this is completely feasible, if rather dangerous. 99% sure it is a real video.
I'm not sure why it makes the 'chuffing' noise though. Anyone know?
I agree with Jonathan. It seems to be a very low-tech, solid steel ring gear assembled and riveted together from 4 distinct parts. Not very aero-spacey at all...
https://bsky.app/profile/planet4589.bsky.social/post/3leq2wb...
There's not any great candidates.