Chosen Solution
If I unplug the laptop, it turns off. It has been reduced to a desktop computer.
I have also noticed that a couple of the battery cells are swollen. Update (09/09/2021) Here are the pics. I hope.
Well, you’ve got a bad battery! As the onboard micro controller chip within it or the connection to your system is not working so the sensor data is not getting to SMC. I would contact the store which sold you the battery (if its new) to get yours exchanged if you can, otherwise you’ll need another new one ;-{ Clearly your systems bath caused more issues here if you are still using the original battery. Time to take pictures of the logic board looking at both sides as you could still have corrosion damage on the charging logic. Post the images so we can see how things look. Adding images to an existing question. Follow this guide to take it out MacBook Pro 15" Retina Display Mid 2014 Logic Board Replacement
@sambodamon If it is bad enough it can be seen with the naked eye, although a magnifying lamp will make it easier to see. Even a mobile phone camera may be good enough if the image can be zoomed in. Here’s an image of what moderate to severe water damage can look like. It doesn’t have to be widespread on the board it can be just little pockets of damage here and there even tiny flecks. So carefully and slowly check the whole board especially around the area where you think that the water may have first penetrated Boards can get dusty over time so don’t confuse what may be just dust (which is not good in humid situations) instead of corrosion. Surface dust may come of with a gentle brushing using a soft brush and a vacuum cleaner whereas corrosion won’t. It needs to be gently removed with a Q-Tip lightly moistened with isopropyl Alcohol 99%+ (available from electronics parts stores). It may turn out that there is none to be seen but you did say water damage so it pays to check. Even though there may not be any more problems now it can occur weeks or months later as the corrosion, if not cleaned away, will continue to erode the metal parts of components which are very thin to start with. Be ESD aware and use a wrist strap connected to an earth point and also disconnect the battery from the systemboard. This will ensure that you can’t damage the board electrically when inspecting it, either by accidentally touching it with your fingers - ESD, or using metal tools and accidentally shorting out components. Golden rule with electronics I was taught more than 50 years ago when working on electronics “Power off first, on last except if needed for testing” Power off in laptops means disconnecting the battery as there is always power on the motherboard, even when the laptop is off. The power button is not a power isolating button.
