I have no UCAS points, will any universities accept me?

Would a Level 3 diploma in Adult Care not give you some sort of UCAS points? You could try taking an Access to Higher Education course online and they'd give you enough UCAS points depending on how well you do. Even if you just barely pass, you'd still have enough to do a foundation year at certain Universities.

Are you considered a mature student (21+) as their entry requirements for foundation years are a lot more lax. Integrated foundation years are basically a year 0. If they're integrated, they're covered by student loans. Some Universities may let you enter a creative writing course based on a portfolio, but you're more likely to need your Level 3 diploma.

https://www.ucas.com/ucas/tariff-calculator
You can find out how much your qualification will be worth in terms of UCAS points there. Should be worth something as level 3 qualifications are supposed to be equivalent to A Level. Whether universities make tarriff point based offers or accept your qualification is something you'll need to query with the universities you're interested in applying to. If they don't Access to HE diploma would be a good idea, that diploma is accepted by many universities, and you can take out a loan or if you qualify get a grant to cover the costs of an access course.

As above, you need an academic Level 3 qualification.
The most appropriate is probably a 1-year Access to HE course - Access to Higher Education (accesstohe.ac.uk)