Starting with 4 and moving to 5 is the best for newcomers. Missing out on the first three is inconsequential, in my opinion. Ought to treat it as backstory. Not much in the way of plot threads shared between games.
It is fixed. Then in some ways worse in 3. Then better again from there.
If 2 gets remade and comes over, people should absolutely play 2. Best story Yakuza has told.