Spilled liquids will leave deposits of junk, even water has impurity / minerals that are deposited. That needs to be entirely removed.
There is a procedure you can try, but it requires completely disassembly. Everything removed. Everything that can be unscrewed from the motherboard, every sticker removed. Electronics Water Damage - iFixit
First of all, to avoid further damage, do NOT power it on again until you’re sure you’ve fully dried it out and removed all the residue. And that includes liquid and residue you might not see that has seeped under tiny chips.
The remaining liquid and residue may be conductive and when you apply power it can cause short circuits which may further damage components that were not originally damaged.
Don’t charge it and if you could, carefully disconnect the battery, being careful of the small pins.
That said, it sounds like you need a new mainboard anyway. Support should be able to tell you more.
I opened it up and it looks like there is some damage to a few circuits near the charging port where the majority of the liquid went, but who knows, maybe it’s even more extensive?
I’m thinking if I can buy a new mainboard & replace it, I might fix this for cheap (the mainboard is like $200)