It depends on what "in" refers to.

If the question is geographic, i.e. Are China and the Soviet Union part of the region called the Middle East, then No. China is part of the Far East or East Asia, which is a very different region. The Soviet Union stretched from Eastern Europe to Siberia, but did not include any part of the Middle East.

If the question is about involvement, i.e. Are China and the Soviet Union involved politically with the Middle East, then, Yes. China needs an incredible amount of energy to power its economy and much of that energy comes overland from the Middle East, from countries such as Iran and Iraq. Therefore, China has a strongly developed Middle East policy. The Soviet Union had strong military involvement in the Middle East using the Arab-Israeli Conflict as a way of having proxy wars with the United States. As a result, much of Arab military craft in the 1960s-1980s was of Soviet design.

Egypt has the Best Military in the middle East after it comes Saudi Arabia then iraq

Because they were going about it the wrong way.

In the Middle East and Battle for Britain against Germany and against Japan in South East Asia.

The Soviet Union invaded Afghanistan in 1979.