Shitty companies ask for real business case problems.
Good companies give unrelated hypothetical problems to test. Eg: a B2B company may give a totally unrelated B2B or even a B2C case. Or ask you how you'd approach something they've already solved.
If they ask for ideas, be vague and on nudging say - at this stage, this would be my capacity for input, I'd be happy to do a case with you to showcase my skills and share elaborate solutions if we agree on my employment.
One chutiya startup stole ideas from me, a senior said this is the way many startups interview for mkt lead positions (how you'd hire and strategize etc)... but fuck them.
I hope many people read this, companies take advantage because there are people who do full assignments.