I can’t get Splendide’s vent kit page to fully open, to view their options. That issue aside, I noticed wasps a time or two near our chrome vent. I see no flapper up inside, and there is an annual problem with mud wasps in our roof air conditioners. They are a problem for anyone working on the roof, much more so working on an AC unit. I thought I might cut a piece of aluminum window screening and bend it’s edges to act as a “spring-loaded” fit into the vent orifice. I wouldn’t think it would interfere that much with airflow, at least not as much as a mud nest. A home dryer has a lint screen of much finer mesh. It could be easily removed to clean off any lint as needed.
I’ve also put mothballs under the AC shrouds with limited success (timing is important), and might try taping one inside the dryer vent opening.
Joel