Backwards compatible feats

So from what I have seen feats/species/subclasses from previous 5e books are backwards compatible with 2024 PHB.
Does that mean that in theory you can take Eldritch Adept feat and Pact of the blade invocation without taking a warlock level?
Eldritch adept says that unless the invocation has a prerequisite of any kind, you can take it. And Pact of the Blade/Chain/Tome?
Not sure how this would be that helpful, maybe on a Paladin that wants to use just Charisma and not bother taking a level into warlock, but does it work RAW?