Climate doomerism - do the laws of physics really say that an uninhabitable planet is inevitable?

So that’s most of what I want to ask right there in the title, but to expand slightly… I feel like this must be a fairly common encounter these days, but for any who haven’t seen - there’s a type of online personality who dedicate their presence to stating that human induced climate change is now beyond our control. I’ve seen many on twitter, they will often go as far as to say that any effort to mitigate global warming is (at this stage) pointless. This is usually hinged on ideas/statements such as ‘it’s physically impossible to remove enough CO² on a short enough timescale to save humankind’, or (one I read today) “There is no scenario that results in lower CO² levels in the atmosphere. Not one. This is a certainty of physics.”. The other most common one is about the cooling effect of particulate pollutants currently mitigating some of the warming, arguing that reducing emissions now would actually cause MORE warming! I know it comes off as fairly hyperbolic, but I’m trying to be sceptical in all directions! I see the work of James Hansen held up as evidence quite often and I’ve read about some of the problems with some of his claims, but don’t think I’ve read comprehensive rebuttals of all his main points. Im hoping someone can talk broadly to the legitimacy of these kind of claims, particularly from a physics point of view. I’d also love to be directed to trusted research that proposes mitigation methods.

Thanks in advance.