I lived there from 94 until around 2007 full time and the late 90s early 2000s were in the midst of the timeshare wars where quite a lot of naughtiness was taking place. I’m on the mainland these days but still have a place there where I head for a few days 5/6 times a year.
It’s nowhere near as bad as it was but like everywhere there’s an undercurrent below the surface that’s best avoided.
Every tourist hotspot has major drug networks working there and being so close to Africa there’s plenty of ways to get stuff in with most traffickers coming from places where life is cheap and they don’t fear any consequences from the authorities.
There’s a lot of places to get lost in and around the hills of Tenerife.