It's quite ironic that Aqua can tell Ruby to not be blinded by the revenge without any hesitation, while he himself is knees deep in it seemingly without any self-introspection whatsoever. Ruby must also tell Aqua the same!
I disagree a bit. As the saying goes, it takes one to know one. Aqua can unironically tell Ruby to not be blinded by revenge, because he understands himself. The difference is, that Ruby has something to live for, a deeply held dream to pursue. Aqua does not, and has a poor view of himself(which in part comes from selfrecognition of how crappy a person he can be, with his manipulation of others for the goal)(if you view yourself as a crappy person, you may have no qualms about bringing yourself down to take out a horrible person)
You can see the pieces of self loathing when his facade is dropped, as he pursues revenge. He doesn't see himself as worthy of something more. And he has been on this path for a decade+ where Ruby only recently took the detour after going her original path.
It would be ironic if he told her that while being ignorant of it himself. But I think he knows exactly what he is doing, and is completely self aware.
His only dream is revenge, and he intends to accomplish it no matter the cost to himself. Taking it all on by himself. Take out the bad guy, and have his stain of existence wiped out, leaving Ruby to have a happy and carefree life without him dragging her down.
That doesn't make him right, or having considered the whole picture well(would Ruby really go live her happy idol life losing her mother and brother dead or imprisoned? Probably not)(Also he forgot Ai's wishes for his life)
But that is where this is the turning point. Where Ruby may get her light back. Where she is reminded of her original dream, and has a second purpose now that she knows Aquas identity. She wants to bring smiles to him as well.
And thus while the Aqua revenge plan is well underway, the save Aqua plan begins.
There are a couple of ways this could end, among them would be helping Aqua find his light. Come to truly realize and accept he enjoys being an actor, feelings he buried for revenge. Of course there are some wild cards like Sarinas mother in play. And it could easily go more dark for a more tragic end.
While I can appreciate a sad ending to stories, or bittersweet ones, I certainly prefer happy endings. Hopefully this ends that way.