Having worked in a wild animal shelter for quite some time I detest those sticky fly traps. We had more than one case of bats gotten trapped by that (yes, inside of flats where bats flew in the open window).
just as an example
https://thefurbearers.com/blog/fly-trap-catches-terrorizes-and-injures-several-small-bats/
I would suggest insect shields in front of windows and doors to keep the flies outside…