Any effect that targets or generates a particular value of a card will only target or generate Jacks instead.
Examples:
Scholar no longer targets Ace, but Jacks
Triboulet no longer targets Kings and Queen, but Jacks
Raised Fist will always pick a Jack in hand, if available
If Idol were to try to select a 5♦️ it instead would select J♦️ instead (even if you do not have a J♦️ in your deck.)
If a Boss Blind targets a card by value (none in vanilla), it would always target Jacks instead
Note, this is an alternative idea to a handful of other Jack of all Trades jokers that doesn't break the rule of wild values, or isn't just "all Jacks are wild suits."
Practically speaking, this will be nearly impossible to implement.