"避重就轻地认罪" can be translated into English as "confess in a evasive manner, glossing over the serious issues" or more concisely as "make a half-hearted or evasive confession".
Here, "evasive" captures the essence of avoiding the important or serious aspects, while "half-hearted" conveys the lack of sincerity or completeness in the confession. The choice between these phrases may depend on the specific context and the nuance you wish to convey.