The promises of devices like neuralink are decades away from widespread voluntary adoption, at least. You can get small things done today, as you could 10 years ago, but they aren't ready for primetime.
Anecdotally, I got a small coated neodymium magnet implanted in a finger during my youth. It was cool as a college student, I could feel strong AC currents/PWM/etc and I never lost small metal parts like screws.
Those were small benefits though, and the risk was quite high. If the coating had breached, my immune system would have attacked the magnet. Accidentally smacking it into things was painful. I was always aware of the intrusive hardware in a mildly unsettling way. Etc.
When I entered a more nature-y phase of my life, I got it removed by a local tattoo artist who dabbled in body mods. They mentioned that the newer versions were much smaller, and would require serious medical facilities to remove.
At the end of the day, active body mods have too little going for them and too many awful failure modes. Passive ones can be fun - I've seen transdermal plastic beads put in some interesting places - but they're hardly transhumanist.