Absolute rubbish and you know it. Who are the mainstream media you refer to? Most written media is massively right wing, usually owned by foreign Billionaires. As most written media is loss making ask yourself why you would bother buying a loss making organisation - it's the same as Musk buying Twitter.
Only a few weeks ago Farage described the Times as being left leaning. Absolute bull ocks of course. Not only is it owned by Murdoch is has previously paid Farage to write articles for it.
No doubt you'll say the BBC and Sky are left wing. Most of their political staff look and act like Tory boys and Laura Kuenssberg is about as right wing as you can get. Both outlets have hounded Starmer from day one. Beth Rigby on Sky has been particularly critical.
Compare the coverage of Starmer accepting a couple of pairs of glasses and suits from a Labour Lord (which was declared) v Farage accepting £5m from a crypto billionaire ,which wasn't declared.
Then the property portfolio that Farage owns and has only partly declared v Rayner not paying £40k of stamp duty, which she has belatedly paid , unlike Farage and the Clacton House.
Then lets look at the coverage Farage gets. When he does a press conference it is often shown live. Why? Has a Liberal press conference ever been shown live, yet they have many more MPs.
This media complaint is just following the Trump playbook who discredits anyone who asks 'nasty' questions or queries the rubbish he states as fact.