Is the actual production of props in film and television dramas infringing?

As you said, it doesn't count, because it's not for commercial purposes and it's not infringement. In addition, the film is full of sci-fi content, and there are no technical parameters to show the feasibility of Iron Man armor. Those functions are directly imagined by film and television authors, and there is no scientific basis to support them. Of course, the development of related toy products will be authorized by the film and television producers. Similarly, it's okay for you to play with only one toy, as long as it doesn't produce commercial benefits, it won't infringe. You can be accused of making a live broadcast of a toy suit. Making small videos with movie elements may be prosecuted, as long as it is commercialized.

For example, if you make a Lamborghini sports car by hand, it doesn't matter if you play with it yourself or crash a Tesla with it. Lamborghini won't sue you. But if you build dozens of sets and sell them to others, then you are infringing.

For example, if you make up a short story about Altman fighting monsters, buy an Altman toy and a monster toy, and then make a small video and send it online, it also constitutes infringement. Such people have been sued by Japanese companies.

For another example, you cracked the drawings and related technical contents of the B2 fighter. You helped China produce a large number of fighter planes for service, which were not used for commercial purposes. Moreover, the state will keep it a secret. No third party will know that this is B2 technology. This is a matter at the national level and there is no way to prosecute. Just like the United States can use a pack of washing powder as an excuse to hit Iraq, but you can't say that you copied B2 to hit China. It's not enough, but it's hard to say that other small countries do this. Diplomatic issues are all about national strength.