Unfortunately, there are a large number of videos and articles on You Tube -- and elsewhere on the net -- that are totally fake or intentionally misleading. While some are written and produced by some very well meaning people, others are simply out there to wreak havoc. I'm sorry to say that you have fallen prey to one of those videos/articles. Dunking your phone in a container of alcohol -- typically people will use isopropyl alcohol -- is no different than dunking it in water. Isopropyl alcohol is typically 30~50% water. Which is about all you need to damage sensitive electronics. Even if you used denatured alcohol, you likely caused damage that you cannot see. Partly because you cannot see the underside of the components mounted on the board, or inside the many sub assemblies (camera, headphone jack, charging port, etc.). People tend to believe that alcohol does not leave any residue when it dries. Unfortunately, this is simply not the case.
Back in the day, we would use freon TF for our precision cleaning needs. Unfortunately, that stuff was banned many years ago, and with the demise of tape decks of any kind, a consumer friendly replacement isn't a big priority. However, I've had some recent success using naptha as a replacement. Naptha is highly flammable, but sold as many products. Lighter fluid, coleman stove fuel, and I'm told automotive map sensor cleaner, are either straight naptha, or a mix of naptha and mineral spirits. Coleman fuel and lighter fluid are both pure naptha.
My suggestion is that you disassemble the phone one more time, and carefully wipe down those parts that you can readily and easily see. Pay particular attention to any exposed contacts. Keep in mind to use a clean, LINT FREE rag or cloth. Never use a q-tip or paper towel. After you've done this, drop everything into a bag of rice and let it sit overnight. The rice will remove any residual moisture that may still exist. Remove the parts from the rice, one at a time (in the order that they need to be reassembled). Use a can of dust-off, or other canned air to blow away any dust that may be present from the rice and anywhere else. This time pay particular attention to all recessed or enclosed contact points. I cannot guarantee success, but it may well do the trick. I recently used this -- successfully --on my daughter's cell phone after she dropped it in the toilet.