You can do the same thing with a relay. Essentially it's the same thing just in a smaller package. The remote wire triggers the relay which in return sends ground to the parking brake wire.
We've had issues doing flush mount USB extensions and them being too long and CarPlay not working. Seems like it loses data through the long run
You right about the relay. I saw some videos on how to set it up but got scared and felt the bypass was simpler/easier.
From a technical stand point, I guess it makes sense, similar to ethernet cords and if you make the length too long, you need a stronger or tighter stranded cord to allow enough room for data to cross. Carplay and Android Auto must require a lot of data since it does so much with the phone. I had a pretty descently long cord once and I remember android auto constantly disconnecting. I thought the cord was damaged but now you make me wonder...