Lib Dems are soft left, neoliberals with a smattering of "maybe racism is bad, maybe welfare is ok".
The Tories and Labour have both shifted far, far to the right. Both are opposed to immigration, tax rises, workers rights, trans rights. Tories took it further with the Rwanda plan, which Labour opposed but did not promise to do anything about.
To me it seems like you have only one option, it doesnt at least look like there are many republicans who would vote for democrats on some election years or vice versa.
We basically do, it's just that your two options depend on where you live, e.g. Scotland, Northern Ireland, etc. but for pretty much every seat there's only one or two people with a real chance of winning