Tories and Reform will complain relentlessly that their votes to seats ratio is so bad, and Labour's majority is wildly disproportionate. Worth remembering this is the system we've always had, which we voted (like morons) to keep a few years ago, and it's suited the right just fine till now.
And when that referendum was forced on the Tories as part of their coalition agreement with the Lib Dems, they made damn sure only one, less satisfactory, version of PR was on offer and then campaigned vigorously against it.
FWIW I am a strong supporter of electoral reform, and I think FPTP is terrible. But we literally had a referendum on it, and I believe those are eternally binding and we all have to suck up whatever unliked consequences they produce, *Nigel*.