I agree, OP. I'm a centrist sort of person politically but have always read the Guardian online and a more relaxing newspaper at the weekend!
I absolutely hate the Guardian now. As you say, the opinion articles are either ridiculous or just plain ignorant and nasty. I sometimes skip to the last paragraph to see how I, as a white middle-class British person, am actually to blame for most of the world's ills. I usually am!
I think it must be somehow different in the paper edition. My BIL and SIL are avid readers - though I admit they're a bit more left-leaning than me, but not much. I think the online edition is focused on attracting a younger, more radical readership (OK, 'woke', along with 'virtue signalling' are the elephants in the room here, so I guess that's what I mean). You certainly find the crazier articles more in your face than when you look at the actual paper, where I do find the arts/science etc stuff very good.
Some people call it the Daily Mail of the left and while that may be a bit harsh, it is very, very far from unbiased and trustworthy. One example I remember from about 10 years ago is:
A news report flashed up at the top of an attack on a man in a Birmingham mosque. It soon disappeared completely - I couldn't find the follow-up anywhere on the website. I checked the BBC and it turned out that it was an 'inside job' at the mosque, a case of violence between 2 worshippers. I strongly suspect that the Guardian was licking its lips at a juicy case of Islamophobia and then spiked it the minute it didn't fit the narrative.
I don't trust the Guardian much more than I trust the DM now.