Since the Trails series is continuous, it's what I think of with this sort of thing. I bounced off of and had to nibble at Trails in the Sky over a good while until the third game hooked me. I never would have gotten rolling with that series without pandemic lockdowns.

Now, Trails to Azure is firmly in my top 5 games.

Dota 2. First time I played it it was not for me, I only played it to hang out with my friends. Many years later I had an itch for it, so I started playing again. And I haven't stopped. It is an excellent game.

Trails in the Sky, the first one. I bounced off the game not once, but twice. I liked the combat, but it felt like all I was doing was quests from the guild's notice board, so I quit. But then I kept seeing TitS (heh) on various "Best of" lists, so I was like "FINE. I'll try to push through one last time". And then it clicked and I pretty much marathoned the entire trilogy.

The first game is good, buuuut I still feel like it's the weakest in the Trilogy. Story-wise, you get to the good stuff way, way later in the game. Everything that comes before is world building. And it's good, too. You get to see how the world works, how different regions of Liberl (the country you're in) operate and you also get a small glimpse of Zemurian politics (Zemuria being the name of the continent Liberl is on). This also gets vastly expanded upon in the second game.

I'm glad I tried it, because the writing is great, the music is incredible and I really dig the combat. If anyone wants to try it, definitely do. Just know that the first game is a slow burn. Worry not, though. Once the plot starts picking up steam, it doesn't stop.

I have two very different kinds of games I did this with.

The first was Undertale, didn't really get into it at first and stopped playing it around half way through. However after I watched someone else beat the game I got a lot more into it and finally beat all the main endings. Really liked the story and it quickly became one of my favorites after that.

The other is the Crusader Kings games. I got one of them when I was pretty young through a humble bundle and did not understand how it worked at all. Then near the end of highschool I finally tried them again along with playing Stellaris and thats when I was finally able to figure out how to play them and got super into a lot of Paradox's games.

Witcher 3

Was overwhelmed with most of the game mechanics.

Horizon Zero Dawn. The first time I played it I could not get into the tutorial, just felt so bland. Then years later I tried it again, pushed through the tutorial, and it's now my all time favorite video game series.

Etrian Odyssey

I tried the demo for the fourth one and just didn't really like or get it. A couple years later Atlus announced Persona Q (which has mostly the same gameplay as Etrian Odyssey) so, I decided to give the demo another try and it just clicked this time. I have no idea why I didn't like it the first time around.

That would be OMORI, first and foremost.

The binding of Isaac. I played about 10 hours of the flash version. 10 years later my friend gifted me afterbirth and repentance and I've played almost 1000 hours