I kinda wish there was more room in the fandom for exploring the toxicity in BaroRyuu. And I'm not talking "Barok bad!! you can't ship!!" I think the flaws in their relationship show up more as Barok's arc progresses and he supposedly drops his prejudice.
A lot of BaroRyuu leans into the idea of Barok doing a 180 and worshipping Ryuu, and Ryuu curing him of his racism because he's just sooo kind and perfect... and like... we do see the problem, right?
The reason Barok is the way he is is that he loved and idolized Genshin. Genshin was the designated representative for all Japanese people in Barok's mind, and when he did something that conflicted with Barok's rosy-tinted view of him... well...
You swap out Genshin for Ryuunosuke, and we're back in the building again. He's just idolizing a new Japanese man and basing all of his self-improvement on the inherent goodness of a single person.
(also part of why he's so attracted to Ryuunosuke is that he reminds him of Genshin :0.)
Regardless of his backstory, Barok's behaviour towards Ryuu was not okay. We all know this. And by the end of the games, it's not like he's fully redeemed himself; he's just on the path to redemption.
(which is why it bothers me when people complain about his "unearned redemption arc". he doesn't have a redemption arc. you would need more time to carry out a full redemption arc. his arc is deciding that he wants to begin a redemption arc.)
It takes so long for Barok to start treating Ryuunosuke with the simple decency owed to him as a fellow human being, let alone the respect Ryuu is owed for being an amazing human being.
I say it all the time: Ryuunosuke has the patience of a saint and truly lets all the prejudice he faces slide off of him like water off a duck's back. Imagine Kazuma in Ryuunosuke's place. He wouldn't have tolerated that treatment at all, and in the process of defending himself and others from such judgement, he'd only be "proving Barok right" in Barok's own mind. Ryuu passively challenges Barok's worldview, and that's why he succeeds. If he had gone out of his way to defend himself or to chastise Barok for his bigotry, Barok would have never let his guard down.
And the funny thing is that so much of Ryuu's patience in the beginning comes from him not expecting any better from Barok. He's not giving him the benefit of the doubt; he just accepts him at surface level. Like, of course, his British courtroom rival would be racist, that's a foregone conclusion. But then, Barok starts dropping bits and pieces of The Lore, and Ryuu can no longer dismiss his comments because "what do you mean your vendetta against me is personal, Lord van Zieks?? I just got here."
Suddenly, the idea that Barok is xenophobic for the love of the game like, say, Jezaille Brett, has flown out the window. Suddenly, it is Ryuunosuke's responsibility as a seeker of the truth to be exceptional enough to be worthy of earning Barok's backstory.
Like come on, that's fucked up... and I like it like that. I don't want to pretend that it isn't an aspect of their relationship. Even on the road to bettering himself, Barok holds Ryuu up to extremely high standards to prove his bigotry wrong. And even when Ryuu passes all of these tests of character, Barok is still begrudging in the little crumbs of respect he's willing to give. It's a long way to go post-canon.
And none of this is me being like "here are all the reasons you can't ship it". I SHIP IT. No, these are undeniable facts about the dynamic between these two characters, and if you ship them in canon, I'd suggest you dig into these flaws because they're interesting.
What I like to explore with Barok's character is that there is no moderation. He goes too far in any direction. He demonized an entire nation of people for the actions of one man who he once idolized, and then he finds out that he was wrong and starts idolizing a new man!!
And you gotta level with the fact that idolization is dehumanizing. When you demonize someone, you depict them as less than human, and you treat them as incapable of displaying any of the virtues of humanity. When you idolize someone, you depict them as more than human and deny them the ability to display any of humanity's flaws. When someone you idolize shows you their humanity, it's so easy to flip a switch, and now they're the Devil.
So, for BaroRyuu to not end in a messy divorce after the honeymoon phase has run its course, Barok is gonna need to tackle his habit of either demonizing or idolizing folks because he can't simply treat all of Ryuu's flaws as nonexistent or endearing little quirks as he gets to know him; he has to allow Ryuunosuke to be a human being or else he's going to backslide. And Ryuu's gotta start telling him off. Barok needs to get more comfortable with getting called out on his bullshit.