I don’t know how to aim my answer for you. You are obviously somewhat sophisticated about MMO play - an FFXIV player trying WoW out, perhaps? - but I do feel like you’re not looking in the right directions.
Here are the Ranged and Healing options
Hunter - BM and Marksman DPS
Mage - all DPS
Priest - 1 DPS, 2 Heal specs
Warlock - all DPS
Balance Druid DPS + Resto Druid for healing
Elemental Shaman DPS + Resto Shaman for healing
Monk and Paladin have Healing specs, but no Ranged oiption
There is also the new class Evoker that will be coming with Dragonflight pre-patch, probably Oct 25, for people who have pre-purchased Dragonflight. Evoker will have one Ranged Damage and one Healing spec. It is likely to be somewhat overpowered in Dragonflight, because Blizzard usually do that with new classes to encourage people to leave their existing classes and play them.
From what you say, BM Hunter is out, and so are all the Warlock specs, with their pets and DOTs. Priest’s only DPS spec is also heavily into DoTs.
Balance Druid really isn’t a DoT class in the same way as Affliction Warlock. You do have a couple of DoTs as Balance, but outside of high-level play you don’t need to treat them in any way special; just consider them instant attacks with a downstream upside you don’t have to think about - it’s just fire and forget.
I also wouldn’t consider Balance especially “hectic”. In WoW, most of the hectic-icity comes from the boss encounters rather than the classes, and ranged classes are less hectic than most melee.
Consider types of content. Different specs play differently in different content. There is World content, or questing. This is the simplest, and least hectic. There are dungeons, which are made hectic by players running like crazy rather than by the devs. There are raids, where the boss mechanics are a McGuffin that may make things crazy hectic. And there are PvP Battlegrounds and Arenas, where your pace is set by your opponents.
In PvE, being in a group changes everything, because you have a Tank to take damage. When playing solo, Cloth casters like Priest and Mage can be squishy in solo and PvP play, and have to spend some time thinking about their defenses as well as attcks, but in a group, the Tank handles thedefense, so you can focus on hitting things!
From what you have supplied, we rule out most of the specs, and are left with
- Marksmanship Hunter,
- Mage, and
- Elemental Shaman.
… and Evoker, going into Dragonflight. Within Mage, Arcane is the most straightforward spec, but that doesn’t mean it will be best for you. The three Mage specs are admirably different, and there’s room for a lot of personal preference.
Shaman and Evoker have healing specs.
Spec have more buttons than are needed for simple play. That is, you may have about 5 buttons for attacks, 2 for self-healing, and 1 or 2 for big cooldowns. And then you might have a whole organ of other keys and pedals that are used in more advanced play, and for niche situations.
To get a sense, you could check icy-veins.com, and for each spec you are interested in, you can compare two pages they list: the “Easy Mode”, or “TLDR” page, which lists the rotation elements you HAVE to know about. and the “Rotations, Cooldowns” page, which lays out the entire class in all its complexcity for people who want to play itto the full.