Is following one monthly current affairs compilation enough for UPSC?

One reliable magazine is sufficient for factual consolidation, as most top-tier compilations cover 90% of the same news. It is better to master one magazine than skim several.
However, it isn't enough for analytical depth; you must pair it with a daily newspaper to understand the "why" behind the news.
Use the magazine for data and the newspaper for the narrative perspective needed for Mains.