Their API deprecated one method with a security risk once and their root certificate is none of your concern if you run a webserver (and it also only changed once and not "regularly"). Their certificate chain is an issue that may concern you, but if your software is working correctly then it should just serve the chain that you get with a new cert.
Whether it's lets encrypt or Google or Apple or Facebook, the internet has largely moved away from a culture of small time hackers operating on barebones standards to super complex implementations gatekept by a few huge companies with infinite resources and conflicting values. They want to curate the web and monetize it, not lower the barrier to entry. You are free to use their ecosystems to produce things they can share revenue from, but everything else will only keep getting harder... what even is the web anymore but marketing landing pages redirecting to walled gardens.
It used to be a web server was something you could almost auto deploy. Then it became a series of increasingly complex steps as various 'security' measures were employed. You can do these things yourself, and they aren't that hard, but they were never made easy in a way that didn't imply a lot of specific technical know how. I kept up with it for a while, eventually everyone has to deal with the real world and it's time constraints, and the 'security' of today provides undeniable barriers compared to the yesteryears of the web.
I'm not convinced this browser change is a good thing - I think the issue is the aforementioned crap on personal networks, not the ability for a browser to go there. If your security is endagered by your shitty dishwasher, either don't connnect it, or since you are doing the connecting, put it on an isolated private network. This move is encouraging bad security practices while at the same time just throwing another roadblock in the way of legitimate uses of 'home' software.
You don't have to stand up your own servers in your favorite cloud provider and become a Cloud DevOps expert. You don't have to manage deployments, dependencies, etc. You can still pay $3/month to get shared hosting on DreamHost, upload your HTML file, and it gets served. No fiddling with nginx, no operating system patching, etc.
Even if you don't want to pay $3/month, I'm sure there are still hosts that will give you a few megabytes of storage and a couple gigabytes of traffic for free.
You don't need much fancy for a plain page, no, but that's also not really what I'm talking about. I still sometimes use local services on my lan, with web interfaces, which are NOT routers, dishwashers, etc. - think file or media management.
honestly, what series of increasingly complex steps? The main thing today is an expectation of HTTPS, and that is added complexity, but also something you can auto-deploy today and lots of tutorials available. E.g. I'm fairly sure I've spent more time of my life on .htaccess and nginx redirect syntax than on HTTPS, despite starting early with Let's Encrypt and not choosing the most-automated solutions - and in other setups "add HTTPS to a domain" is literally a line of config file, with the webserver doing the rest. But that's beside the point I made:
This is assuming that you actually are deploying something to a server, instead of making use of the myriad of ways of having that be someone else's problem. How are those "essentially" not true options?
"We can trust users and random developers to do the right thing" is understandably not the security position browsers take, so this needs some solution eventually. What the right tradeoff is is a good question. (i.e. IMHO there should be clear ways for devices to opt-in to being accessed)