Forgot to mention that, yeah I also played heartshstone in past 4 monhts, and it just get bored really fast.
If you dont mind old rpgs for example like “The Legend of Dragoon” that was on ps1, but it is really good and the storyline really awesome.
I dont know if this one is considered jrpg but it is made in rpgmaker - that kind of 2d stuff, and it has one of tthe best stoylines imo. Its a classic but I hope someone like you will enjoy it. Its called “Last Scenario” and i loved it. It approximetally has like 2 weeks of gameplay or maybe even more.
I nolifed it and it took me 3 weeks of nolife 24/7 days to complete it and I dont regret it.
If you are interested in it go check it out, its worth a try and also its FREE!
Both of these games are turn based as you wanted.
here is a link to last scenario:
http://site.scfworks.com/?page_id=8
