Any smart home stuff. The story with Amazon shutting down someone’s account and all their devices is terrifying. Frankly I should probably unplug my smart speakers.
The Apple Watch is neat for health stuff but I don’t see a need for another device to charge.
OLED and Mini/MicroLED screens for PWM sensitivity. Even LED lights are starting to hurt my head.
To expand a bit, search "home assistant" or "hubitat."
Both are great, but home assistant is open source, and has the bigger community who support more devices. It is a bit more DIY than hubitat, but they have released their own hardware to go with the software, so its getting easier all the time. You can also run it on your own hardware if youre handy.
Hubitats advantages are an all in one hardware/software package and a philosophy that aims to emulate the cloudless Smartthings of yore (the old lead player in stand alone home automation until they lost their damn minds). It is still a ways DIY, but is not FOSS. Still, active community and tons of supported devices.
I tried home assistant a while ago and I couldn't wrap my head around yaml that it uses and I couldn't seem to get conditionals to work like I wanted them too. I'm not a great coder but it was not nearly as easy as I wanted it to be.
Id recommend giving hubitat a try then. Its more gui focused, with tasks being "if this, then that, except if..."
They support a wide range of apps/devices out of the box, but also have direct to import community code/addons. A lot of the smartthings devs moved over to hubitat, so the community is solid.
Unless youre in a rush, they often have $100/hub sales around major holidays too.
+1 look for devices that support Zigbee or Z-wave (or Matter now, I guess) as these are all guaranteed to have fully local control with no internet connection required. Install Home Assistant and connect via a VPN to access it while you're away from home.
I unplugged my Alexa speaker last week because I needed the outlet for something else and haven't plugged it back in. Never use the thing. I have a Google home mini that I really only keep around because I enjoy being able to turn my window AC on by saying "reroute power to life support".
The health stuff is a bit overblown anyway. On a day to day level it's just junk data.
There's so much variation between both between people and also for one person just depending on how they feel that you can't tell what a particular number means.
There's some argument that heart rate is useful for high-end cardio, where you want to keep track of exactly which heart rate band you're in to be sure that you're at capacity but still clearing all the lactate from your system. However, given how much these numbers can vary if you haven't slept fully or you have a bit of a cold, or you overate, you're probably better off learning to pace yourself.
The health stuff on the Apple Watch is basically just for entertainment at this point. Which isn't to say it can't be useful, I definitely know people who have gotten more active because of the "gamification" of things like the activity rings.
If your watch reports say, a single atrial fibrillation event in any otherwise healthy individual, it doesn't do a whole lot for you. Even if you bring that information to your doctor, they can't be expected to do much with it. They could strap some additional monitors on you, but if it is a very rare event there isn't much chance of it recurring when they are actively looking at it.
In some cases, the anxiety caused by worrying about it can actually cause more issues than just not knowing.
I actually like my watch a lot, but more for just a notification device/convenient payment interface rather than a health tracker.