Hello, your question really interested me. It is true that sometimes pest repellents do not work, but there are hundreds of reasons why this happens, from improper installation (not enough range) to counterfeiting of the product. But my experience with the pest repellent has been very positive. I live on the outskirts of town in a private home and we are constantly getting different types of insects in the house as well as mice. My father gave us an insect repellent which is plugged in and can additionally serve as a nightlight. And the very night we turned it on we clearly noticed fewer insects, we could say it was an accident, but further use of the pest repeller showed that it really works and helps. So I can safely recommend the pest repeller
https://www.crioxen.com/products/ultrasonic-plug-in-pest-repeller-by-b223
They also have a portable repellent and in general the products are very good quality for not much money. So I recommend trying it, it seems to me a good and effective way, I personally checked.