For financial advice on 5M, I would probably go to
@Marc (Marc Westlake) for advice. He puts out some of the best content I have seen (check out everlake/his feed on linkedin). And from his content, and some past posts on this site, he seems to think very holistically, about how to maximise investments, including minimising total tax burden on you and your family over your and their lifetime.
I can's say if I would actually 100% follow's Marc advice, as I haven't used his services, or seen what an exact plan would look like from him. Based on some very old post on the site, IIRC, He seems to have some very specific investment packages that he has setup/brokered/deisgned. They may well reflect the best solutions available, but without them being fully discussed in open forums I would remain a bit nervous.
E.g. I have seen him raise things like US estate tax, tax efficient investing for your kids, using pension for tax benefits, even when the contributions are not tax relieved, based on tax free compounding and/or inheritance tax planning. And he also seems to be very aware of hidden costs in funds etc.,