My dad struggled with that for years. But he played golf and wasn't a cyclist. If he had been I'd have suggested the types of saddles designed for triathletes or time trialers, or the even more minimalist saddles that are little more than pads for the sit-bones -- although I wonder how practical those are on the road when leaning into turns. I'll have to ask a friend who tried one on his trainer to cope with saddle sores.
But a recumbent may be the most practical solution. I'll probably switch to a recumbent eventually, due to chronic neck pain from a permanently damaged C2 vertebra. It limits the time and/or distance I can ride a conventional bike, usually to around 20-40 miles.
Unfortunately the lighter, faster types of recumbent bikes I'd prefer are much more expensive. But I suppose that's the price of wanting comfort and a responsive machine.