Is there any way to use Dexterity for spellcasting or as a named spellcasting ability?

Question

I've always wondered about creating a character who trains to use every spellcasting ability.

The publication of Bigby Presents: Glory of the Giants introduces the possibility of using Strength in a ranged spell attack "as the spellcasting ability". The Keenness of the Stone Giant feat can increase Strength by 1, and the Stone Throw feature says:

As a bonus action, you can take a rock and make a magical attack with it. The attack is a ranged spell attack with a range of 60 feet that uses the ability score you increased with this feat as the spellcasting ability.

And with the spells selected with the Aberrant Dragonmark feat (from Eberron):

Constitution is your spellcasting ability for these spells.

This suggests the possibility of combining further feats or multi-class spellcasting to collect all six spellcasting ability scores in one (terrible?) character … if Dexterity can be used in a similar way.

The Way of the Sun Soul Monk has a strangely worded Radiant Sun Bolt ranged spell attack feature which doesn't mention a 'spellcasting ability' but does say:

You gain a new attack option that you can use with the Attack action. The special attack is a ranged spell attack with a range of 30 feet. You are proficient with it, and you add your Dexterity modifier to its attack and damage rolls.

Are there ways of getting Dexterity as a named "spellcasting ability" anywhere?

Answer 1

In Eberron: Rising From the Last War the variant Human with the Mark of Passage gains the innate ability to cast Misty Step with Dexterity as the spellcasting ability.

Magical Passage. You can cast the misty step spell once with this trait, and you regain the ability to cast it when you finish a long rest. Dexterity is your spellcasting ability for this spell.