Is there a reliable, not too biased source/website to read about what airlines are best to take for what routes?

For example, I’ve flown BA and AA to LHR direct & it was an awful flight (tiny seats & super uncomfortable) & would’ve paid more $$$ for a better airline but I couldn’t find a reliable website to help me understand who generally has better seats (pitch, width, etc) and all that.

I’ve resorted to my own spreadsheets for flights (I know…) where I put the different info down & then compare prices. It’s not awful but damn, it’s a bit time consuming.

For context, I’m not an overweight individual I’m just willing to pay extra to not be crammed into a tiny seat with no pitch for 12+ hours.