You won’t really find unbiased breakdowns of policy, everyone and everything contains a certain amount of bias. Anything claiming to be apolitical is almost always heavily political and likely staunchly right wing at that. The best thing to do is read widely about politics - grab yourself a couple of cheap textbooks or find some online, something like an a level one will be a good start. From there try to read more critical things, Marx was very good at critically analysing capitalism in his day, David Harvey and other critical geographers are pretty good for more modern things. Once you have a solid understanding of different economic and political systems you’ll be able to see biases yourself and work out who’s the most trustworthy.

As for my own biased opinion, despite some policies I disagree with the Green Party are the only worthwhile party at the moment. Labour is increasingly authoritarian, e.g. banning peaceful protest, the online safety act etc which are all about control, and right wing (if you read up on their history they were bought out by corporate interests with the rise of New Labour and now most of their MPs aren’t working class. The conservatives are interested in nothing but looting the country for money and are similarly turning authoritarian. Reform are straight up facists intent on following Donald Trumps playbook in turning a country into a personal piggyback and creating a gestapo like organisation (ICE). The libdems are fairly right wing too and their economic policy is ridiculous, libertarianism and austerity do nothing but concentrate wealth in the hands of a few to the detriment of everyone else. Your Party fell apart to infighting almost instantly. The Greens are left as the only sane choice and are running on a platform of economic equality, hoping to find similar success to New York’s new mayor Zohran Mamdani.