2014 Pathfinder Transmission issues

My dad’s 2014 Nissan Pathfinder recently started having what we beleive are transmission issues. as we attempt to accelerate it feels like the transmission is “slipping”, or put differently the car starts to shake a bit and it feels like power is not being applied to the wheels. we think its transmission related because when we put it in D or R it takes a moment and the car is almost like it’s in neutral before power is applied to the wheels. it takes 3-4 seconds now for the power to get applied, and then it feels like its “slipping” . i dont know if my description of the problem helps but its the best i can do. my dad said he reseached some info online and apparently this is a problem that nissan knows about but is not doing anything about to fix. he mentioned it might be a software related issue and had mentioned that some people had the problem fixed when a combination ofa valve was replaced with a software update. he said he already had the value in question replaced a while ago so im not sure what to do here. hes going to take it in but i'd love to be able to offer some helpful info as i fear this issue is going to be expensive. thanks!