There is no video, witness and physical evidence of a plane crash on the building in question. Building 7 collapsed either as a result of a fire due to debris from another building, or from a controlled demolition. The way building 7 fell into itself was indistinguishable from controlled demolition.
Finding out that WTC 7 was brought down by controlled demolition does not automatically implicate a grand conspiracy by the U.S. Government. However unlikely, it could be that explosives were in the building to minimize damage to surrounding buildings in the event of possible collapse.
However, it is not disrespectful to 9/11 victims to question the official narrative. It is dangerous to accept ideas without doing your own research and critical thinking.
The effects of planes filled with jet fuel being flown into buildings with steel frames have not been scientifically tested enough to provide sufficient evidence that it could not have caused the demolition of a building.
You are correct in that no plane hit building 7. Debris from the North Tower did; and started fires. According to reports from NIST, the building in question lacked sufficient water sprinkler systems. This lead to an extended burn time and reduced structural stability leading to collapse.
I repeat that no steel structured high rise building in the world has ever been brought down by fire, especially in a vertical freefall in its own footprint. Only controlled demolition can result in this phenomenon.
Fire is one of the greatest threats to the steel structures due to the temperature rise. Steel structures are designed against the yield strength which drops rapidly with a temperature rise. The yield strength drop causes plastic deformations and change of the structures designed geometry.