"Link to a related item" available only when editing existing item, not when creating a new item.

@1Passworder1 – I think we both agree on the makeup of the problem at hand: you're making an item and want to use "Link to a related item" before saving it. In this case, it's the item you're creating that doesn't yet have a UUID, and that's why it must be saved first. The link is essentially "the item with [this UUID] is linked to the item with [that UUID]". Because both of those aren't yet known (given that one of them doesn't exist yet), the link can't be created.

I'll pass your feedback on to the product team, however. Maybe with some work in the future it'll be possible to link to an item while in a "draft" state. I don't know when (or even if) that change would be made, it must be said, but I'll add an internal note explaining your preferred workflow.

ref: 29838681