Well I googled it and came on this website: https://www.autoexpress.co.uk/best-cars/101118/top-10-most-comfortable-cars-on-sale
Their list is this:
1. Mercedes S-Class
2. Rolls-Royce Phantom
3. Range Rover
4. BMW 7 Series
5. Bentley Mulsanne
6. Audi A8
7. BMW 5 Series
8. Bentley Bentayga
9. Audi Q7
10. Mercedes E-Class

But personally I would say you want to make a test drive before actually buying a car right? Also I think Volkswagen cars have done a lot in comfort wise. I've had a Volkswagen myself as well. Maybe you should sit in one of those as well. Just test different cars out. Before you even make a decision.