I have many nerdy friends who have been Linux users for ages. But most of them don’t know such a thing as Openwrt exists or have never bothered to give it a try. It’s a very fun piece of software to play with and can be extremely useful for routing traffic. Wondering why it isn’t more popular/widely used.
Most the things you mentioned are barely doable on some of the modern all in one modems where I live.
On mine I’ve got separate wi-fi networks for inside and guest, I run zenarmor for ads and malicious junk, I run a proxy, I do my DNS on it for all my internal docker instances, and more. I realize I am doing more than your average person, though.