I'd argue it's actually the Tories who are good at getting rid of individual PMs, the 1922 Committee gives their backbenchers a built-in regicide mechanism and the wider party has a culture of using it; even surviving the vote can hole a PM below the waterline. Labour leaders are harder to remove, Jeremy Corbyn for example survived his attempted deposition in 2016 and Reform's leadership entrenches the party leader further still. Having said that recent events support you more than me maybe, since Labour successfully deposed a sitting PM much in the same way the Tories repeatedly did.

Of course any PM still depends on Parliamentary support, by definition the Prime Minister is the one who can convince the monarch they can form a government which has the confidence of the House of Commons. My complaints of presidentialisation are more in the centralisation of power around Number 10, Blair was particularly known for it but it's been basically all of them in recent history.