STORY TIME :D
(I'll leave a TLDR at the end)
I actually started out maining ADC.
Didn't start dipping my toes into actually playing support until I tried out ranked for the first time (I played League for near a year before I touched ranked).
Tried playing ADC but it wasn't working out. Supports had control of 99% of the lane phase and mine always seemed to be clueless.
That's when I picked up Zyra for the first time.
And I actually started climbing pretty easily. I even skipped a division in Silver, but decided that was as far as I felt like climbing, and went back to playing nothing but ADC and Taliyah in norms.
The next season rolled around and I figured I'd continue to go that route for ranked. Plus, this was the beginning of season 8. Supports, especially ones who could build ardent, were strong as fuck.
I picked up Nami and was able to absolutely destroy my placement games going 8-2 and landing myself at a solid Silver 2, a division above where I ended last year. I had learned a lot since then, and was able to carry a bunch of games and found myself around Gold 2 for a while, where I eventually was stuck for some time.
I kept up this for a while; ADC/mid in norms, support in ranked.
Until I tried out for my college's League of Legends team.
I saw this as an opportunity to try and get back into playing more ADC again and improve enough to climb with ADC in ranked.
Unfortunately, I was but a wee gold player. The only two diamond players trying out were both ADC players.
Wanting to have the best possible shot at still making it onto the team, I tried out for mid primary/support secondary.
This really upset me because I knew if I made it I'd likely make it as a support, and I really wanted to break out of that. Half the reason I wanted to join was to learn and get better at ADC. I hate the stereotype around girls only playing support, and its really not my favorite role to begin with.
I played mostly mid at tryouts regardless, and crushed it.
I was considered heavily for the mid spot, but it was ultimately decided that they could get the most out of the roster if they placed me on support. Go figure.
That's when things were pretty much sealed.
I started picking up and playing new supports to expand my champion pool, I played more ranked than ever before, I practiced pretty much nothing but support.
I've improved a ton in a very short time, even if its not necessarily the role I want to play the most.
Ended last season in platinum, and managed to get to diamond pretty quickly this season.
Playing on the team has been a ton of fun, too.
Easily the most fun I've had since starting college.
So that's why I play support.
ADC is more fun in the regard that you get to be the one running around killing everyone and there is a lot more mechanical skill expression IMO.
Support is more fun in the regard that you have a TON of agency in the lane phase, and are kind of the mastermind behind the scenes of your team.
It still makes me kind of sad when I do a ton of work to win lane, the ADC gets fed, and they're the one getting all the honors, though.
Sorry for the novel, kind of got carried away with explaining there.
***TLDR; Mained ADC, supports in ranked were bad, started playing support to climb in ranked but still played ADC in every other gamemode. Tried out for my college's League team, got selected as the team's support, now I play support all the time. ***