To deliver a vertical slice you also create hacks left and right and they quite often then later stand in the way of actually delivering a proper product. I remember the blog post by Ron Gilbert where he presented Da Vinci's Vertical Slice [1] and it still sits with me as one of the best way to present the issues.

A vertical slice is not an MVP because people would never consider it minimally viable. It's a tiny product but it's completely polished and it's for a consumer of one: the publisher.

[1]: https://grumpygamer.com/vertical_slice/