They are easy to kill. I’ve done it. Twice. In two different homes. Diatomaceous earth. To get them to bathe in it, you have to use their own feeding patterns against them. They were in my 8 year old daughter’s room and bit up her legs. So I put fairly deep plastic containers with D.E. in them under each of the four legs of her bed. I put helpful “ramps” to the containers, so they could easily walk up to them, but then they fell in, and there was no getting out. The D.E. slowly kills them over a number of hours, slicing their shells and they dehydrate and die. After 3 days the dishes were filled and no more were to be counted. Never saw them again. In the 2nd house, the infestation was a bit worse, and I repeated the process, but using homemade CO2 emitters (yeast, sugar and a 2L bottle) with the same D.E. setup. Took a week, but they all died.
Once a year I buy a big bag of DE a put it all around the fenced in yard where we keep the beagles.
DE kill ticks too.