While they could not export towards Western countries, semiconductor devices formed a significant fraction of their exports to the Soviet Union and to the countries dominated by the Soviet Union, i.e. to the other members of the Comecon.
If the GDR had not used most of its resources for a greater development in the domains of semiconductor devices, precision mechanics and optics than most other members of Comecon, it is likely that they would not have been able to export much except food, which they did not have enough even for themselves, while needing to import a lot of resources that they did not have.
If Asianometry had made a video with the similar title "How Semiconductors Ruined Intel", that title would be closer to the truth, because during most of the last decade the performance of Intel in developing semiconductor manufacturing has been much worse than that of the GDR.
Hopefully the woes of Intel will end this year with the launch of the "Intel 4" process, but before that Intel has succeeded in 6-7 years to transform an advantage of 2-3 years in semiconductor manufacturing against all others into a handicap of 2-3 years compared to the top competitors.
By contrast, GDR has started with a handicap of at least 10 years against USA (the US semiconductor industry has been created in the middle of WW2, for the fabrication of radar diodes) and after some 35 years it still had about the same 10 years of handicap.
While GDR and the other communist countries have never been able to reduce the technological gap between them and USA, they also never had any such tremendous fall behind, like Intel, where it seems that the management methods and the internal cooperation between divisions have not been better than those that were rightly criticized for GDR.
Unfortunately bad management is not an exclusive feature of the "planned" communist economies, but it becomes more and more frequent in the present economies that have become dominated by quasi-monopolies everywhere.