It’s not really a guess. It’s plain obvious why Top Gun Maverick failed to pass censorship in China.
The movie was partly sponsored by Tencent and Paramount even offered to remove both the Japanese and Taiwanese flags from the jacket to appease Chinese authorities.
However, still that wasn’t good enough and as a result Tencent was forced to completely disassociate themselves from the project because they didn’t want to offend the powers that be.
Since the beginning of the US-China cold war in 2018, China has been clamping down hard on US cultural influence and promotion of US military.