Can a liquid damage to my MacBook Air get repaired ?

Apple replaces parts and in the case of liquid damage that likely means the entire logic board.

Liquid damage is a user-caused event and is not covered by the one year warranty. If you have the extended warranty, you may get the replacement at a reduced cost.

My 2016 13" no touch MBP logic board replacement was $592US three years ago.

Your referring article explains it well.

Same comments apply.

Water damage can be delayed and in many cases is. If the damage is showing, it will either remain as is or will get worse.

You think the KB is still working? Is it or not? Easy enough to test that.

It sounds to me the device got pretty well doused if there is water in the screen and the ports are malfunctioning. And that sounds like the beginning of total failure. Or at the very least the Mac will be running but unusable.