What is the best method for drying my phone after it has fallen into the ocean?

See the sections about an iPhone getting wet:

About splash, water, and dust resistance of iPhone 7 and later - Apple Support

Per Apple: “Don’t put your iPhone in a bag of rice. Doing so could allow small particles of rice to damage your iPhone.”

Seawater is corrosive, future problems due to that corrosion would not surprise.

You need to face the fact that your iPhone is not repairable. There are, at least, two reasons why:

1. A liquid with impurities, like sea water, has worked its way inside. Even if you can completely disassemble the phone and dry it, it will leave conductive residue. When powered on, this residue can cause short circuiting and further damage the phone's sensitive electrical components.
2. If you powered it back on after recovering it, without fully cleaning it (not even possible), you potentially damaged it further ... as mentioned in the first item.

Apple does not repair liquid-damaged phones, nor is this type of damage covered by their hardware warranty. I'm sorry, but there is no "best method" to dry this phone.

Do NOT put the phone in rice. Tiny rice particles get into the ports and openings and then expand, clogging everything up and preventing water inside from evaporating.

Stand the phone on end and lean it against a wall or other surface so the ports are at the bottom of the phone. Let the phone dry for at least 2 days. Then, give it a try.

Unfortunately, it sounds like the phone has already been permanently damaged by water....salt water is the worst....and will be a total loss, since Apple will not attempt to repair a water damaged phone.

Rice is not effective at all. That's a myth.

Your phone is not repairable. It will have to be replaced.