The phrase "acknowledged expert" refers to someone who is widely recognized and respected for their extensive knowledge and skill in a particular field or subject. Full definition
The magazine covers both new and emerging markets, with articles written by acknowledged experts who either live within the market they're reporting on, or who have intimate knowledge of it. (accolade-wines.com)
But our school leaders seem to lack the desire, or perhaps the courage, to formally acknowledge expert teachers and to identify and work with mediocre teachers for improvement. (teachermagazine.com.au)