Acceleration lost/gain after turning head lights off

Velrod43

2009 370z auto, 150k miles. Recently started losing acceleration and Rpm will not go over 1.5-2k. Only when I’m driving with lights on and doesn’t do it immediately, usually after about 30 min of driving. I believe it’s a drain somewhere but shows 14v on dash, and battery has 12.9v while off and 12.7 while running. Also, when I say loss of acceleration I mean 40 mph max flat surface and will newly come to a complete stop on a long hill. A few times It has picked up and drove normal for a few minutes before reverting back. Just wanted some input before I take it in. Besides that only other issue is minor condensation in tail light which I will replace (not sure if that will make a difference but have seen threads where some said changing that fixed electrical issues).