It's really hard to start an alt that in future should become your main

if i wanted to heal being hybrid wouldn’t be a problem and i wouldn’t try to change main

Everything and every weapon is for warriors.

You don’t tell us what you like doing at 60 with your “main”: raiding, Mythic dungeons, battlegrounds, world pvp, whatever…

Nobody does them all. And different sub-classes (there are 27 in Classic) are good/bad at each.

So step 1 is deciding what you will do.
Step 2 is picking a class to do it with.

I feel its completely the opposite. You did list the only 2 fights where actual damage goes out that you can heal and are fun as a healer. All of the other fights are a joke to heal. Some of them can be done with 2 healers. I take it easy using no consums ending up with tons of mana and still 75% overhealing. Then you usually have 10 healers in a raid with potentially extras sitting out so you have a ton of gear competition. Then when you win an item well who cares its only more overhealing. My healer is my alt because I knew this but tis still boring me.

Just pick a warrior so you can be broken for the entire game.