Murong Qingyi is so complex, actually. He has low self-esteem and nearly absent survival instincts, but he'd go feral for the people he cares about, ruthless to a murderous and suicidal extent.
It seems that for him love = pain, in some variation. Either suffer for the people he loves, or by their hand, or, alternatively, simply because of them. He and Susu seem to be speaking a very similar love language. While she's at the point where she doesn't want him to get hurt, when he does - and for her - that actually comes through to her in ways no confessions ever could. Because he's doing all the bonkers stuff for her, even competing with her, who's more sacrificial. I think he's low-key trying to guilt-trip her into staying by his side, and while it never worked before, it just might at some point XD This is all a skewed example of 'see and be seen' by that other special person, just accompanied with a hefty amount of violence.
Da-ge never needed proof of Qingyi's love, I feel it's always been a more or less unconditional familial affection. And still, he was the one who sent Qingyi to prison (and Qingyi suffered his hand injury there because of his brother). And that moment in their teens when Da-ge was suffering to help Qingyi, experiencing quite literal physical pain, once again establishing the love = pain equation in Qingyi's mind.
He knew very little love, and the people who were supposed to take care of him while he was growing up - were either violent or abusive in some kind of way (the only type of love he actually knew before meeting Susu for the first time).
In all of the scenes we've seen since her coming back - he's selfless to the point of throwing his life away for other people. Either to prove/show his love (in Susu's case, and she does get the message), or to help his da-ge and his girlfriend (not because the Huos are despicable and need to be obliterated, but because they're hurting his people). He didn't go on a vendetta rampage mission for himself and what they did to him, but rushed into a fight headfirst without thinking - for all those other people that he cares about.
He's broken in so many ways, and it's so beautifully portrayed D: That man needs decades of therapy (but with the amount of men he's already finished off, that probably won't help at this point).
