I think the reason different people like such different size iPhones is their different use.
Some people consider the iPhone just a quick reference device on the move and they use an iPad or MacBook for most online usage- for those people the easy carrying small iPhone may be preferred.
Then for others, they don’t even posssess a tablet or laptop- and in this case use their iPhone for everything including games and video playing. Obviously they will prefer a Max size phone.
Then those that always wear jacket or carry handbag. A Max size causes them no inconvenience, so they will also naturally go for larger phone with easier viewing.
We are all different. There is no right or wrong answer. Go for what suits your requirements and lifestyle. It is good there is a choice and we have left the days of having no alternative to the 3.5” screen