They've gone downhill in the last few years in my opinion, they've become more overtly partisan and got substantially downgraded on factual reporting by MediaBias Fact check: https://mediabiasfactcheck.com/the-guardian/
They've always been left of centre, but they're lazy and jump more into the predictable culture war pandering.
The FT is streets ahead of anyone else, they've become more centrist and less dry in recent years. I don't know what their revenues are like but I'd wager that they're doing better as they're one of the only ones with a business model that allows them to pay for good journalism.
If they were "left of centre" that would be fine there are few if any major left-wing newspapers in the UK. The pandering from my perspective has been to those on the right. They seem to be doing the "well if both sides hate us we must be doing something correctly!" except the right want rivers of blood and the left want public transport, healthcare and to ensure the more vulnerable among us are treated with dignity and compassion.
The "culture war" people refer to is not "woke ideology" being pushed everywhere as is so often the accusation, but an enormous, orchestrated push against an otherwise fairly organic process where the world had otherwise become more naturally more accepting of immigrants and LGBTQ+ minorities.
If you think the Guardian panders to those on the right you need your head examined. I would love nothing more than a left leaning socialist government and even I shake my head at some of the nonsense the Guardian publishes, especially in their opinion section. It's an effort to get clicks and cause outrage and some of it is no better than the tabloids.
I also disagree that there has been a "fairly organic process where the world had otherwise become more naturally more accepting of immigrants and LGBTQ+ minorities". That's a rewriting of history. Equal rights for the LGBTQ+ community were incredibly hard fought for over many years. It's been anything but organic. It's important not to forget how recently most of the civil rights we take for granted in many areas of life were rights that were denied by a majority.