[Claude's goals]

However, as a character, he is very believable and realistic. Without getting too into real world politics, 

Claude is very much reliant on other people to progress his own story.

He has some interesting ideas, but as charasmatic as he is, hes never going to do anything by himself.  Hes going to try, but he isnt taken seriously pre-skip by more or less anyone, his own house is super iffy about his ability to lead, and he does things that make Byleth go "uh... wtf is this guy on about this time". The only way he manages to end up with any amount of authority is because Edelgard started a civil war and he was the de facto leader of the "nobody cares about you enough to make sure they murder you first" faction.

 

Post skip, he's in a bad way.  The alliance is pretty tattered, most of them are either aligning with Edelgard or Dimitri either publicly or in private, he's reliant on Byleth in every route to help him accomplish basic tasks, in Judith to talk what little sense he has into him, and he only ends up capable of surviving (not even beating, at this point) Edelgard because surprise, I'm from Almyra and have ties to a famous military leader who is totally okay with tossing his troops into the "we didnt really exist yet" third position of the fodlan civil war.  It's a Claude gamble that either works or ends up being the most disastrous Claude'ing ever.  Like "I just got our recently war-torn fodlan and almyra into a continent spanning war, in which most of the people who entrusted me with power will be fighting on the opposite side, and also theres no guarantee I'm not going to accidentally be shot a few dozen times on accident by my new team should I survive until that war starts" disasterous.

 

And as bad as that is, without Edelgard kicking things off, Claude is, at best, the leader his own people rebel against within a few years of him Claude'ing it up in the Alliance. Theres several families who jump at the chance to do that the second they realize they can without the rest of the Alliance really caring all that much.  He is a fantastic supporting character, but needs to be regularly saved from himself.