That is true: the Soviet satellites in the Middle East were largely secular. Militant Islam started to be a problem for the Soviets only after they invaded Afghanistan; but as the other side of the coin, modern militant Islam grew out of the Afghani resistance.
The Orthodox Church of Russia fell to Sergianism — collaboration mode with the Soviet regime in the late 1920’s, I believe. This did not purchase them much if anything: the priests were murdered, parishes closed and churches blown up all the same. There was a small reprieve when Stalin had to hustle the war with Germany; the moment the war was over the reprieve was over also. Khruschev “predicted” that the last church in the USSR would close in 1980; it came close to that.
It is also true that with all atheistic brutality that the Orthodox faced, other Christian churches and denomination in the USSR fared much worse. Baptists and Catholics were simply seen as foreign agents and ended in the prison system massively.
I am not aware of any comparable oppression of Islam. Perhaps I am not informed. Serious oppression of Judaism started when the Jews began to emigrate, in 1970’s. Of course no religion was viewed favorably in the USSR, but the Christians, and especially non-Orthodox Christians or Catacomb Orthodox Christians were markedly worse off than any other religion, in my observation.
Mosques were shut and turned into sheds etc. The crackdown on all religions was hard, but Islam was a particular threat to the communists due to its link with nationalism.