That's not a small request. And, you're right, it is overwhelming. And depressing. Here are some random thoughts.
* Automation across devices outside of a corporate environment is hard.
* List all your devices that you're willing to spend time updating. That can get out of hand quickly.
* Turn on auto updates IF the device supports it and IF you trust the source of the updates. You can set auto updates at an app level too. Do I trust MS to update Windows? I did with Windows 7, which I still have. Would I with Windows 10. I'm not so sure. They keep breaking people's systems. Do I trust Google to update my Android tablet. Well, no. At this point, I think Google is one of the MOST evil companies. So, I have Android set to not auto update apps. I manually update the ones that I think might relate to a security risk, including the AV, various web browsers, VPN, email sometimes, etc. Most other apps, I don't update unless they stop working. The other reason I don't always auto update is updates break things and change user interfaces that I'm used to. Do I allow the tablet to auto update the system itself? Again, usually no. If I do, I have to spend hours going through all the settings and checking them to make sure something wasn't changed that wasn't in my best interest. In terms of my Windows PC's apps, browsers are set to auto update, email is, I update the VPN as needed, AV is on auto update. Most other things, I don't update unless I need to. Everybody will have different answers to these things.
* Do I auto update IOT things. NO, I don't own IOT things. If I did, my answer would depend on how much I trust the company not to snoop on me, lose my data, or break my device.
* Do I auto update routers? NO. But, I'm running DD-WRT and I have ALL external features turned off. If you update a router, at least in the past, you have to reset all your settings. So I leave it be and let it run.
* Having said all that, routinely patch or autopatch all the things you're comfortable with.
* Don't expose ANYTHING you don't need outside your firewall.
* Segment your LAN to separate your IOT if you have IOT.
* Reduce or eliminate things that use firmware AND are connected to the internet.
* Listen to Steve and Leo every week.
* Evaluate your risk exposure to new threats and determine if they need action AND, if you're willing to spend the time on it based on your analysis, KEEPING in mind the philosophy of not exposing anything outside the firewall.
* Periodically run
@Steve 's Shields Up against your external IP address.
* Be aware that things like cable modems / routers can be remotely reset and programmed by the cable company and can change their settings. I recommend running your own router that you control behind theirs toward the inside of your network.
* Explaining this to your parents or grandparents or even probably your kids is difficult or impossible.
A networked device is a bit like adopting a pet.
@PHolder is right. There's a lot involved. At this point, your eyes may be crossed and you may be throwing your PC across the room. That usually doesn't help. This may help psychologically. I don't think anyone who isn't willing to spend many hours per month on device maintenance can keep up on all this, especially if you have a few PC's, a few tablets, and a few phones.
* Try to pick and choose the most dangerous threats and evaluate your attack surface. Focus your time on the few critical things. Some things you can ignore for a while before they get to be a problem.
* Separate topic, but don't drive an internet connected car. If you do, try to disconnect it.
* Take some time away from worrying about all of it periodically and let off some mental steam, peacefully.
Sorry, but I don't think there is a simple easy cheap fast automated solution. But, then again, you probably don't spend too much time worrying if an asteroid will hit your house. It's catastrophic but unlikely, and you can't control it. So, pick your battles. Most people don't worry about any of it. They just use their devices and defaults and hope nothing happens. I don't advocate that. I don't think most here would. But, you still have to strike a balance that doesn't drive you insane. Also, understand that you can only do what you can do, and you can only control what you can control. Try not to fret too much about the impossible or improbable. And, I have to take my own advice.
See, I was able to ignore at least 10 other things while typing this.
Hope this helps.
May your bits be stable and your interfaces be fast.
Ron