Tried to challenge negative thinking for years. Why am I more negative than ever??

I have tried most of the stuff. Being mindful of my actions, challenging negative thoughts, writing them down, journaling, have recently started therapy. I've been on antidepressants before and they did not work.

It is genuinely exhausting to keep acknowledging and challenging my negativity. I don't know what to do. I've tried cutting out social media (yes i know reddit is social media, i come here to ask questions when i can't find answers elsewhere and thats it), I've been avoiding the news, etc. Recently my thoughts have gone from negative to outright hostile and angry as opposed to general negativity. I am trying, so hard. I have a self help book, I've been practicing mindfulness for years, and it feels like nothing I do is never enough. I feel like I'm just getting worse and worse.

Sure, the world seems worse than ever before, but that can't be the only reason. I think I am outwardly kind and compassionate, I feel deeply and I try to understand where people are coming from, people have told me I seem very bright and nice and whatever. On the inside, I feel like I'm rotting, just becoming more and more negative. I only seem to have a positive thought if I'm being distracted from reality.

What other mindfulness techniques can I try? I feel like I've exhausted all my options. I'm afraid that I'm becoming a terrible person, or that I always have been and I've just buried a monster under a facade of good deeds.