Netflix recommend 25Mbps for 4K.
I believe youtube 4K is 35Mbps to 70Mbps depending on framerate... but I'm not 100% sure on those figures, perhaps someone is more across this.
In *theory* that means you could probably squeeze by with Netflix 4K. Youtube would work but probably with a fair bit of buffering.
The issue is that even for Netflix, you've got no headroom there. If anyone else in your apartment is using the Internet, you'd hit buffering. Also, despite selling you "24Mbps", lots of ISPs also aren't able to deliver your full bandwidth at peak times. So it might work fine at 3am, but buffer like crazy at 8pm most days. It's also usually extremely difficult to find out what happens at peak times ahead of time. You could certainly ask the ISP sales team what sort of service-level-agreements are in place. They should be able to tell your what the minimum performance you can expect, but you can bet they won't guarantee you the full 24Mbps 100% of the time.
Do you have multiple ISP options or are you stuck with the one choice? You could perhaps try explaining your situation and negotiating an early exit clause if their service isn't able to deliver the full 24Mbps consistently. But then again, if you only have one choice it's not like an early exit clause is much help.
Unfortunately the short answer is... good question, try it and see!
I realise that's not much help though.