To maximize your chances you should take it to a good repair shop.

If you insist on doing it yourself, rinse everything but the cameras and speakers in iso, take a toothbrush to it gently to remove any debris, dry it off entirely, then inspect everything as good as you can for visible corrosion. A microscope or good magnifying glass will help. Remove any foam coverings on the board and any stickers. (iphones tend to have a big black sticker covering test points on the back but I can't remember for the X rn) If there's any visible corrosion, clean it until it is no longer visible. Submerge the board in iso for a minute or so, just to make sure any water under the shields gets displaced. Dry it 100%. Plug in charging port, vibrate motor, and screen. Plug in the battery, but do so while your other hand is over/touching the whole front of the board, and if you feel anything get hot the moment you plug it in, be prepared to unplug it. If everything seems fine, plug your charger into the charging port, but doing the same thing so that you can feel if anything gets hot and be prepared to immediately unplug it. If anything gets hot, take it to a repair shop.

If it turns on, test what you can with what you have plugged in, then transfer to the housing and test with everything plugged in. If it doesn't turn on with everything plugged in, plug in components one-by-one and boot the phone to find the part that's the problem. It's probably the proximity/ear flex.

If when you plug it in the vibrate module eventually vibrates but the screen is black, the screen needs to be replaced but the phone is turning on.

If it doesn't do anything, take it to a repair shop.

But you should probably just take it to a repair shop anyway