Literally all that matters is winning the election, by as large a margin as possible, and that's exactly what they've done.
How can a huge majority be anything other than a brilliant result, to suggest anything else is just saltiness.
That's not how things work.
A large majority is traditionally the worst outcome for any party. As weird as that seems.
With no effective opposition, there are no "checks or balances" in the house of commons. The party with the massive majority doesn't need to unite and eventually starts to fragment, making it impossible to lead and ends up in fragmentation.
That's exactly what we've seen in the Conservative party since they won their massive majority in 2019.
I'd also point out that Labour won their landslide victory with only 35% of the vote.
So that means that 65% of the electorate voted against them, and didn't want them in office.
This inevitably will mean that those 65% will feel disengaged with the Labour party. That doesn't bode well for an incoming government, so I'd expect Starmers problems have only just started.