Oh god I remember watching the 2019 anime but getting really confused a few episodes in because things just seemed off and like I was missing something. When I searched for it the next day on the site I was using showed the 1998 OVA "series", and I thought it might provide the context I was missing. And oh boy it certainly did, just not in the way I expected...
Never knew it had such a big role in Visual Novel history. That's cool to learn!
I find that most people I talk to had positive opinions of the late queen, but as you said are apathetic towards Charles at best and disturbed by Andrew. Prince William seems to be highly regarded though.