iPhone X boot loop after (slight) water damage

On vacation I accidentally fell into the sea with my iPhone X. It was just for a brief 20 seconds until I got out of the water. The iPhone continued working for a long period, but I noticed that my Face ID was currently unavailable. Later that evening, my iPhone died and I wanted to charge it. This was working fine, until I needed my iPhone, not knowing it was water damaged, I unplugged it causing it to die again a little later. From that moment, it wouldn't boot up anymore and it got stuck in a boot loop. Now, I realised that my phone was water damaged. I decided to put it in rice for a day. After that, I tried to boot it but it didn't do anything anymore, not even showing the apple logo. I was worried because of this and decided to let it rest a couple days more in the rice. After that, I charged it and it did boot up -> showed the apple logo -> then died again. I thought that my battery was damaged, so I decided to replace it myself. This fixed the problem of my iPhone dying but now it's just back in the boot loop. I stumbled on some YouTube videos and saw that the boot loop may be caused by some water in the connectors. I decided to clean all my connectors with isopropyl but unfortunately this didn't fix anything. I'm kind of worried now because even none apple repairs are really expensive in the area where I live and as a student I saved really long to just buy this phone, let alone buying a new one. Is there anything else I can do or try that may fix the problem? I do really appreciate the help! Thank you so much in advance.

Some sidenotes:

- the iPhone barely looks waterdamaged when I opened the phone

- I saw some vapor in the Face ID before I put in into rice, this is already gone