In fact, I consider Paladins unnecessary.
For me the standard in a base class is that you could have a group of six players show up for session 0, and each one wants to play a character with the same class, but each player wants to play an obviously distinctive character with their own separate shtick.
For some classes it's fairly obvious how you could do that. You could have six wizards for example each of which has their own school or theme of magic that they specialize in. Likewise with cleric if the rules supported it well, you could have six clerics each of a different deity who would be as different as the deities they served. Or you might have six rogues, each of which specialized in a different sort of larceny, forming a heist team.
In many editions though, this has not been something supported well by the game. 5e has made a step in the right direction by bringing back subclasses and making subclasses for all base classes, but traditionally classes like fighter, barbarian, druid, ranger, monk, and paladin have failed my test - if for slightly different reasons. Fighter fails the test because for the most part it's been pigeon holed into a very narrow list of things it is good at, which I think does an injustice to the class. Barbarian, druid, ranger, and paladin though to me all fail the test because they all have tried to define what is basically a character concept and not a base class. It's telling that most of those began life as subclasses themselves.
There is a fix here, but it's a radical one. I think you have to pull back from your preconceptions and ask if something like Paladin is a subclass of some base class, what base class is it really a specific implementation of. And my answer for that is NOT fighter or cleric.
To me a Paladin is a specific concept or subclass of the base class 'Champion', which I define as a class in which the source of power of the character is being selected to represent some idea as the idealized representation of that idea. A Paladin for example is a Champion of Justice and Righteousness. This is similar to but distinctive from a Cleric of Justice and Righteousness, though presumably the Deity of Justice and Righteousness might want both priestly servants and heroic representatives. When you view Paladin as a sort of Champion, it becomes immediately obvious how you might have a party of six champions each of which is very different than the other. It also becomes obvious why Paladin isn't a subclass of fighter, since the rules overhead in supporting each Champion concept as a separate subclass of fighter is much larger than the overhead in supporting each Champion subclass. All of these Champion subclasses will have much more in common with each other than they will ever have with other fighter subclasses.
As further evidence, I submit that all the Blackgaurd, Anti-Paladins, Paladins of Freedom and other attempts to create variant paladins we've seen over the years that are like a Paladin but symbolize different things and beliefs, are just the general recognition by the community that there was something wrong with the paladin implementation that they couldn't quite pin down. I didn't know what the solution was until I saw Green Ronin's 'Book of the Righteousness' and it's 'Holy Warrior' class. But the problem with that class is that it didn't build the class in such a way that you could create your own concept by mixing and matching different ideas - they basically just outlined classes specific to the setting. So I set out to rewrite that class in a way that you could in fact generalize the concept.