FLOORING

My only thought is that the laminate planking will offer you a little bit more structure for the spongy floor.  It may not be enough though to cure the problem. You may want to remove the current vinyl to get a look see at the condition of the underlayment. Just some thoughts.

Starting pulling up vinyl,,,,,,its soaked ,,,,,,obviously from condensation,,,,,ya, laminate i think is best for stabiity,,,,,I have both in my house,,,,,needs to dry out before i can do a further eval,,,,,not sure how to addreess spongyness

I would suspect a leaking water connection, maybe a bad toilet valve? I just saw a video from a full time van lifer and they had a similar situation and discovered it was a very small leak in a water connection at the sink. If you have an outdoor shower, check it as well water will make it's way between layers in wall panels. Leave no stone left unturned when looking for a water leak. Good luck.

Can you determine the epicenter of the spongy flooring? Water is a funny thing and can travel a long way out of sight to puddle and cause damage. Maybe the water pump has a small leak and over time it is the cause. As G has pointed out the cause can be any water line connection in the trailer.  I have a 179 2019 and the water lines run under the vinyl and luan flooring in a cavity that was created by removing the styrofoam.  The water lines are running east and west in the trailer. Can you determine if the bottom side of the flooring has been compromised in the same area that you see the damage on the top side of the flooring? There are many spots where the water maybe coming from, good luck in finding it. 

Once that underfloor has been compromised, I think you need to fix that before you put anything else on top of it.