1st: the UK never voted for Rishi Sunak. Truss (also unelected) left and the Conservative party internally chose their new leader, who they appointed as PM since they're the party in government.
2nd: most people in the UK vote against the Tories and always have. All they need to do is get a couple of percent above the next most popular party and it gives them 100% say. The worst part is that if another anti-Tory party comes around, all it serves to do is split the anti-Tory vote more, and hand them more power.
It's our voting system that is broken. People in general do not like the Conservative party.
To clarify for those who never lived in Britain and as I explained above:
In the UK even as little as 37% of votes cast (which can be less that the votes from 1/4 of voters, due to abstention) can translate into a 50% + 1 majority in Parliament and the country has no written Constitution, so a simple majority in Parliament can easilly changing laws around things most people consider essential, unlike in countries with Constitutions were certain things can only be changed with 66% or even 75% - depending on the country - of parliamentary votes.
People in, for example, the rest of Europe, get all surprised when the UK government just makes demonstrations de facto unlawful and add extreme requirements for labour strikes so that it's extremelly hard for unions to organise them, because in most of those countries, unlike the UK, changing such essential rights is not something a party that only got 25% of voters on their side can do whenever they feel like it.