Game is too difficult to play, am I missing something?
Many good tips by MiKaEl here. To expand on a few things though:-snip-
Don't be afraid to spend Skillpoints. You can always reset them for free as many times as you wantto shuffle them around. Some choice early-game picks are maxing Mira's healing, buffing Brad's Fearless Charge, and definitely definitely maxing Ryoko's Party HP Boosts as soon as you get her. If you're gift spamming to 70, don't forget to get Ryen's 'Gift Boost' skill before you do, then after you're done gifting, reset it and distribute the points elsewhere.
Trey is a hidden gem of a party member. He's a tank, yes, but TBH he's inherently tanky enough, so you should build him for speed. IMO his best Aura is the MP regen, especially when you pair him with Mira, but the other ones are good in specific situations if you're having trouble. When you have the research building unlocked, give trey the 'Power Up!' skill. His inherent damage is lackluster, but between Cover recasts he hasn't got much else to do, so make him the party buffer.
If you're using the walkthrough, consider unlocking the Hidden Onsen scene with Mira and Mirel ASAP, and let him keep the peephole open. The sword he gives you will be the best option you have for a long time, and pairing it with the Katryx Blade when you craft it will probably be your permanent set up until you can start running Raids.
When you have a little free gold to spend, consider crafting 5~10 Soul Lanterns, so you can start doing MonsterGirl hunts. Particularly Imps. You are going to need a lot of Imp Hide to craft better gear with Alchemy.
Special Arrows are basically useless in the early game, but they sell for a pretty penny when you're starting out. Free Mirel early and sell the arrows you find in the chest there for a nice kickstart to your economy.
Always explore every nook and craney of each new zone you find. There are Skillstones hidden all over the place. And you only need one rope, ever, not one for each hole. It doesn't get consumed.