The antonyms for "more maintained" can be "less maintained", "neglected", "abandoned", "dilapidated", "run-down" or "shabby". When something is well-maintained, it is regularly cleaned, repaired, and taken care of to keep it in good condition. So, the opposite of it would be anything that is not taken care of or left to fall into disrepair. For example, a neglected building or property might have broken windows, overgrown vegetation, and a general appearance of being run-down. A dilapidated structure might have a sagging roof, peeling paint, and creaky doors. While "more maintained" implies something is well-cared for and in excellent condition, the antonyms indicate the opposite and are indicative of a lack of attention or care.