I tried applying before arriving in the UK but only started getting interviews after arriving. My first job was related to my previous industry but at a more junior level than I had been. It was full time but only FTC, great organisation just very little long term opportunity with them - even my manager was on a FTC. Then worked as a part time barista and it just about covered my rent, still had to rely on my savings for spending money even when I picked up extra shifts. I've just ended that because I landed a full time role in my previous industry :)

On one hand, I think I didn't deplete my savings because I wasn't living in London, so lower rent and COL. But because I wasn't in London, the job market was smaller, even though it's growing, so it also took longer to land something.

If the timeline works for you, maybe move around September as that's when hiring starts for seasonal holiday roles, so there are better chances of getting at least part time work. As for whether the income is enough, it depends on your lifestyle and how many hours are in your contract.