1 get 3 1st level wish spell and wish can cast equal level spells instead of one lower

2 get 2 2nd level wish spells and 3 1st level wish spells

3 get 2 3rd level wish spells and 4 2nd level and can cast 1st level wish as a cantrip/infinitely

4 get 1 5th level wish spell and 1 4th level wish spell in addition to all previous wishes and ignore the necrotic damage for using wish incorrectly and use 1st level wish as a bonus action and 3rd level wish as a reaction (overrides the one spell slot action/turn rule) can also cast 2nd level wish a cantrip/infinitely

5 ignore all downsides of wish and have wish as every spell and your only spell (can use 4th level wish as a bonus action and 6th level as reaction, can use 1st level wish for 10 minutes to regain all spell slots for self)

at level 20 ignore all limitations of wish (at dm's discretion and if you have all 5 wishful thinkers) and NOTHING can stop you from casting wish (with the exception of being dead for 12 seconds)

at level 20 may use 9th level wish to have infinite spell slots until next long rest

Must be able to cast wish to gain this feat