All three, lmao.
I played Runescape daily, subscribed via the old system that charged your phone bill with my parents thinking the phone bill just went up (so shitty lol). Probably still one of my personal favorite games even though I do sort of wish I had that time back.
Ragnarok I spent the second most time with, I played private servers because I don't remember it being free or there wasn't an international version at the time? I liked servers where the rates were ticked up to kill the grind and treat it like a normal game, the custom items and NPCs and everything else people made, etc. I put in so much time figuring out how to convert the game to English downloading the client with a Japanese IP address. Now that I think about it, trying to play a lot of English-converted foreign MMOs taught me a lot about computing in general. I also remember how long it used to take to download 500MB-1GB based on how many attempts I made at downloading the client on dial up.
I played MapleStory the shortest of all of those. I played that with a group of people on the pet site Subeta I think? I can't really remember. I thought it had the slowest grind overall, I felt like I was doing nothing and asked to spend money incredibly often. Most everything felt inaccessible for free and the equipment for characters under the max level was awful.
I literally would try any free MMO, the idea of playing with other people used to be THRILLING to me but it was a different environment. If you look at the "Free-to-play with microtransactions" list of MMORPGS on Wikipedia, I would have played most of those and never purchased anything. If it wasn't too much fun and incredibly grindy and had a huge paywall to fun ratio, it ended up I'd play about a month like MapleStory. If it went towards the opposite of those, it would be treated closer to Ragnarok. I think Runescape felt special because I had a unique way to pay for it.