Nothing worse than feeling lost like this.

I think it's important that you spend some time really thinking through two things:

1. When do you lose track of time/enjoy getting lost in something?
2. If you could invent a job, what do you think it might be?

Once you answer these two questions, you can look at the overlap between the two and start to see opportunities that might be a good fit for you. For example, if you're really into the outdoors and you loosely want to stay in the software space, you could consider applying for outdoor brands like Patagonia or North Face (not sure what equivalents are in the UK but you get the idea). Sometimes we can't always get the job we exactly want, but being in the right ecosystem (in this case, outdoor gear) can help give us a sense of purpose.

If you wanted to do something totally radical, you could look at something like National Park Rangers. I know here in the US they have a massive shortage of rangers and they're hiring folks any chance they can get. It most likely won't pay what you were experiencing at your SW jobs, but the upside of being outside, not being stuck behind a computer, and the sense of being on adventures each day might be well worth it.

The point here is to find spaces that your interests and skills overlap.