The internal/external address split problem only goes away if you have a provider independent prefix, thats not in reach for many due to cost

Using both GUA/ULA together solves enough to get by, but its not ideal

That's kind of my point. In 20 years of managing networks and infra, none of those things have ever been painful or cost me more than a few minutes a year. That's just not enough to convince me I have any reason to switch over.