Good news from me - even if it is too late for the TO, I want to share my experience with two iPDPRO 9,7" which fell both in a bathtub several years ago...
I liked to hear music while in my bathtub and had a sort of little table to put my iPad onto it while themselves in a third-party case.
After many years, one of them glided into the bathtub and it took me some seconds to get it out.
Same with a second one two years later although I was sure that the other case would held it in position... bad luck.
One of them was immediately turned off after recovering and dried with a towel, the other one could not be turned off no more and "died" some minutes later.
I absorbed the resting water in the lightning-connection of the iPad immediately with soft paper and a "Q-Tip" to have less risk of a short circuit for more than just a minute.
So, I bought a new one because I was already thinking about purchasing an 11" M1 iPad.
There have not been very important data on them and I lost only data of the last 2 months (last backup) . So - no catastrophe at all.
I accepted that sh*t happens and that ithey will either be lost or get back to live one day - and put them for a week to a (modestly) warm place .
And charged them 1x each year using the little 5 W charger of my old iPhone although they never ever woke up or showed something on the screen after trying to put them on...
And just two days ago, after some years, I connected them again with my old 5W iPhone-charger .
And when I thought the first one has been charged I realized that one of them just went "ON" spontanously - and works perfectly now - even all the data are still stored !
The other one had also been charged but its screen stays black after trying to awake it.
So - maybe coffee, Coca Cola salty water at the beach might be much worse and accelerate corrosion of the contacts and so on - even if you give up your iPad after drowning completely in water because reparation will be too expensive or you are already thinking about a new purchase before this happend.....
... Just dont give up and perhaps you can give it a try....
I think it was a good idea to wait at least a full year before trying to recharge because a short circuit can be dangerous (risc of ignition AND FIRE of the iPAD OR ITS LI-BATTERY) and you should be VERY prudent. BUT... if you charge them once a year in an ABSOLUTELY safe place and under permanent supervision there seems to be a certain chance that it will dry completely and recover again. And you might have a chance to recover data that you did not yet backup before the accidental problem.
Since I still have all my old iPads (purchased my first one 2012, an iPad 3,3) as a sort of second "backup" because they are worth nearly nothing after 3 or 4 years I now charged all of them with my little old 5w-iPhone-charger (less fast and therefore perhaps less dangerous) and even the iPad 3,3 (2012) has still all data and works well. Even the batteries seem to be in a good condition... maybe the very modest warming while charging with the "under-dimensional" 5W-charger helped to get there.
Except the single one with the still defective screen .
So - perhaps these old iPads can then easily serve for other things like remote controle for your NAS, music-server, TV , or so.
