Welcome to the forum good first poist that’s a big issue. Its always hard to nail down noise things. They can be tricky.
Sounds like you walked down the proper path to find where this is coming from. Without really getting into it there is a possible chance that once the oil thins out the lifter starts making noise.
Now I have worked on several cars where if you let the motor sit for several days the lifters would colaps and it would take a long time for them to come back up but generally those are only when the motor is cold.
After you did the seafoam did you see any difference in the one area where the oil was not coming out smoothly