Just to contribute as I just fixed this same problem on my 2018 LG dryer, so after 5 years enough lint built up through air leakage to cause the issue. The problem was lint under the filter holder , you have to remove the filter holder , four philips screws on the inside the 2 screws on the front outside of the dryer opening are not involved . You cannot get to the affected area for cleaning without removing the holder. The whole job takes 20 min. , the 2 self tapping screws at the extreme ends of the holder are a little hard to get back into the sheet metal.
