Antonyms for the phrase "most high level" include "lowest level," "least advanced," and "basic." These antonyms indicate a lower or less advanced position, rather than the highest or most advanced state. For example, a beginner in a particular skill may be operating at a basic level, while someone with more experience would be at a higher level. Similarly, a low-level task might be simple and straightforward, while a high-level task would require more expertise and preparation. It's important to keep in mind that antonyms represent a range of levels and positions, rather than providing a single opposite to the original term.