Regarding Scotland, it's worth pointing out that (so far as I can tell - correct me if I'm wrong) we haven't seen much polling breaking down different regions.
It's not entirely certain that we'll see the same shifts in Greater Glasgow to the rest of the Central Belt, the North East may be different again and the Borders and Highlands might also go their own way. It's also not clear how much tactical voting we'll get and to what extent it will be on unionist or anti-Tory lines.
So whilst on UNS the Labour vote is pretty efficient and the SNP vote very inefficient, whilst the Tories are holding up surprisingly well, it's possible that things could be either better or worse for all those parties depending on if there are significant regional variations.
Sunak has 100% placed a bet on Labour to win.
Only question is whether that's nationwide or for his constituency.