It's definitely harder than the normal games (this is just to justify the breeding and creating new and powerful pokémon) But I will say you get a bit more tools to work with early on then in H version, I try to provide you tools to help with difficulty. If a particular fight is too hard then I would most likely provide a sidequest or an item to help ease things a bit. I think there's two fights that might have to get nerfed but I want to see how people handle them first. As for grind the grind comes in the fact that you have to buy items to raise affinity of human characters and to raise obedience of special pokémon, So money gets tight. Again if it's seen as unfun then I will provide ways that people can crease their funds. I just want people to fill accomplished when breeding lol.
I mean I saw what you are saying. but as somebody who's been gaming for 40 years (not joking), and conqued some pretty touch challenges in that time, I'm going to encourage you to go maybe a slightly different route without compromising your goals too much here.
Your average gamer sucks at games. Period. That is the truth.
They don't want to 'learn' a boss, or do more than 10-15 minutes of grinding/farming in a play session or they are out. You should shoot for no more difficult than the original games, or people are going to nope out of this game fast. Sure, there are people who want a challenge, but when most people are h-gaming, they want a game that isn't going to make their brain work too hard or stress them out. Again, everybody is different but there are common themes - but I feel given the number of "too hard" comments I've seen on other games I thought weren't bad....people nope out of challenges in h-games.. But if too many fights are winning by the skin of their teeth (and maybe after 5-10 failures) you will lose people quick.
My real advise (that I mean to say earlier) add an easy more that just double all exp, items and money received. Combat and what not stays the same, but now you've given people an option who just want to experience the game, without being challenged by it.
Best of luck, do as you will. But when I see conversation about a game being challenging, it's a red flag.
tl;dr Most people aren't going to play your game (or any hgame) for a challenge, so why alienate potential backers/fans of your work. People don't watch most porn for plot, same applies here for "gameplay" difficulty.