>>16928308
The usual order is Ark(Ys VI) then Oath(remake of Ys III) and finally Origin(prequel to Ys I), to see how the combat evolved and perfected during these 3 games.
There are two more things I should tell you: As another anon said, don't worry about continuity, since the games are more or less self-contained.
1. If you want a hardcore experience, you have to play it on Nightmare. Will you get frustrated and die a lot? yes, but almost every boss fight will be an adrenaline rush. Don't worry, these games do not have NG+ modes so Nightmare was designed with a level 1 Adol at the start.
2. This is not Dark Souls, you can not beat the games at level 1 with the worst equipment. You will just do 0 damage to the mobs/bosses and you will get one shot by everything(at least from my experience). You will, from time to time, have to grind enemies for experience and gold to buy/upgrade your equipment, that is a reality you need to accept, thankfully you don't need to spend hours on it. Even speedruns of Ark, have to delegate 10-15 minutes to grinding mobs, it's just the way thing are. Now I can assure you, that grinding does not make a boss fight easier, it just makes an "impossible to win fight", into a "barely winnable fight, holy shit I can't believe I finally defeated this boss". I am not sure if at some point mobs stop giving experience if you are over leveled, but there is diminishing returns from them(say that at level 1, a rat gives 10 exp, at lvl 2 it gives 7 exp, at level 3 it gives 4exp) and of course to reach more difficult mobs, you need to defeat the bosses, so there is rhyme and reason to this.