Water damage. you have a leak somewhere. Looks like been leajking for a while. Underneath that sink is obvious water damage as well. If the wall area with the "snake" is next to that cabinet that is as good as anywhere to start,

I would say water damage too. Why are there shims under the baseboards. You need a base moulding on those baseboards, since they are not done well enough, to not have one. Find a reputable plumber and start with hiring him. A lot of your problems could be water leaks.

Are you in a cold climate? It looks to me like an ice dam issue, similar to what happened to my house. Built in 1967, totally renovated in 2014, my baseboards and walls under North facing windows look like your first photo. My issue was recent and just once.

https://extension.umn.edu/protecting-home-rain-and-ice/dealing-and-preventing-ice-dams

Google, in your area, for a specialist to come take a look.

Make sure he/she looks at the basement...to me, it might be another issue.

Thank you for your responses, @millworkman the snake looking part is behind close to behind the cabinet I showed with the water damage

@cat_ky sorry but what is a shim? 🤷‍♀️ and well I’ll find a plumber but then what type of person do I need to tell me if i should discard the wood and /or knock down the wall?

@elcieg I’m in northern Florida interesting tho

A shim is what shows up under baseboard in I think its picture 2. Picture 3 shows the base molding, that is missing in picture 2.

You would need a reputable contractor (not always easy to find in Florida) to determine anything structural.