US *admitted that there is no spy equipment on the balloon.

Once again, you are making things up.

The US said the spy balloon was certainly capable of spying, but it did not collect information over the US, in part because of the American response.

"We're aware that it had intelligence collection capabilities, but it was our -- and it has been our -- assessment now that it did not collect while it was transiting the United States," Ryder said during a briefing, adding, "As we said at the time, we also took steps to mitigate the potential collection efforts."

And does it explain how air currents can add two thousand pounds of equipment to a balloon?

You should read the articles before you link to them. This one describes normal weather balloons, which are far smaller than the Chinese balloons and can only travel about 100 miles.

Sure, it's possible that China deployed a completely novel type of weather balloon. But if so, it should not be surprised by the interception of its unusual balloon when it entered US airspace.

For that matter, if you designed a brand new weather instrument that was carried in the back of a Cessna, and then you flew that Cessna into Chinese airspace to carry out your measurements, then you should expect to be intercepted and probably arrested. After all, Mathias Rust was sentenced to four years for violating Soviet airspace.

I'm afraid you are the one making things up. The article doesn't say anything about balloons following air currents, quite the opposite:

That’s because balloons still offer unique advantages: They don’t disturb their surrounding environment, they’re very gentle on scientific instruments, they can hover in one place for extended periods of time

Normal weather balloons are far smaller and incapable of crossing an ocean. The Chinese balloon was not a normal weather balloon.

But real weather balloons do not follow air currents. They ascend and descend over the same point, so that they can be easily recovered by real scientists. Real weather balloons are also far smaller. Various scientists, not just Americans, said that the Chinese balloons did not resemble the instruments they use.

There have been multiple incidents of Chinese balloons that "flew off course" and ended up over sovereign airspace.

If China doesn't want its balloons destroyed, it will have to do a better job controlling its "research instruments".

And The Guardian referred to it as a spy balloon right in this very article.

Incidentally, the Pentagon said it did not collect information over the US. Perhaps it was intended to collect information elsewhere.