I used to main two characters at the same time, but life got busy, so I’m only maining one now. What I main, depends on a bunch of things. I tend to gravitate towards healers lately, but I have mained tank for two expansions, and mained DPS before that, too.
My main content is m+, I play it for fun. I don’t care about class, or progress either, really. I just want to have fun, is all. Right now, that fun happens to be pushing keys, and am enjoying my shaman a lot. Prior to that, I loved playing resto druid last season, and mistweaver in BfA. Prior to BfA, I had a break between end of WotLK and 8.1. In vanilla, I played warlock, and a shaman twink. In TBC, I played prot warrior. Started WotLK as the same prot warrior, but switched to DK for Ulduar and beyond. I had a few alts on the side (disc priest was my main alt in wotlk, didn’t really have anything in TBC), but didn’t play them much.
As for the future? I have no idea what I will be playing next season. Maybe the same shammy I main now, maybe something else, maybe I’ll quit. We’ll see. I’m not emotionally attached to my characters on unhealthy levels - I can leave them, and the game behind without a second thought and no regrets. I do have fond memories, however, and treasure those. I never delete characters I have fond memories of, just move them to the bottom of the character list. I do fear the day I reach the character limit, however… but then, maybe I’ll start another account!
I do have a lot of alts (16 max level toons at the moment, and a whole bunch of others at 50, waiting for 9.1.5), and some of them have decentish gear, in case I decide to switch mains. They’re nowhere near my main, but they have enough gear to hop into weekly +15s and not be a huge burden, and be able to pull their weight, as one would expect. I have switched mains during shadowlands a few times, and… the first was painful. So I learned my lesson, and keep some alts in reserve, to make any future switch much easier.
Some of my characters have a story, others don’t. Come to think of it, the only characters I have a story for, are my Gnomes (and Mechagnomes), and this druid (but even this druid has a mechagnome connection, hehehe).