The planet will be fine
Humans may cause their own extinction, lots of other species will be extinct, but the planet will continue to turn, and new species will develop, and nature will grow back over the ravages left by human destruction.
Well, that was what my dad used to say back in the 70s. We had an allotment, never ate out if season veg/fruit, never flew anywhere, cycled most places, never used single-use plastic, mended clothes instead of buying new, bricks in the toilet cistern, etc.... he is 83 now but his carbon footprint will be tiny compared to lots of us.
Ahead of his time? In the 70s quite a lot of people lived like this. I grew up with it, it's second nature.
But the really big issue is the growing population, and that is not in the UK.
And micro changes in individual households in the UK will indeed not change the fate of mankind.
I think we are already past the point of no return.