I have had a phone in the muddy bed of a river overnight. Washing was a matter of agitating it in a bucket of clean water three times for about 5 minutes each time.
With an oily residue wash, dry by shaking followed by hours of drying with an air flow then use very strong alcohol to misc with any water and oil. Isopropyl alcohol is most often used as it can be bought at strength 99%+
As you will have no warranty you can also take apart the top and bottom modules for further cleaning
Sadly my old phone was s simple Nokia with a removable battery, no complicated module to clean and connect. It worked fine after a day but these more complex phone’s are more difficult.
But as mentioned do not try and use the phone for a day or more, just clean, dry and rest.
If you have a friend or fairphoneangel near you that can help you may be able to swap some modules to test.
However if the battery is charged ??? you should be able to boot the phone with all the modules removed, hence testing the core module.
All the best