I only know the basics of networking, so I’ve been wondering why this “DNS-sinkhole” functionality can’t simply be implemented directly in private routers (as some kind of blocklist) instead of adding a new device to your network. Do routers not support this for technical or security reasons?

That’s why I love my Fairphone 4. Everything about it still works like back when I bought it 5 years ago, except for the replaceable battery. And it will still get security updates for a few more years