I understand. I do want to point out that the quests aren't exactly made to be optional. Yes they can be, but you will miss out on all sorts of bonusus and extra characters. They are basically paralogues and shouldn't be skipped as they were made first and greatly influence the game and the main story pales in comparison. You can unlock more dialogue options but gaining side characters and doing quests and you can get limited items. You will have many empty character slots in battle if you don't do the quests. Also if you didn't do the quest "Warriors' Way" by chapter 3's ending you will no longer be able to do it ever again. Useful characters such as the machinist Astren who uses a gun and Kefaro who can turn into a dragon and wreck things are side characters. A normal fire emblem game is around 22 chapters. Falnarion Tactics is roughly 12 chapters. There are 27 confirmed side quests. So again when you skip the quests, you are skipping about 60 percent of the game. Also the thing about the combat is that there are so many enemies because the premise is for the battles to go as quick as pokemon fights. Not very effective- low damage. Normal attacks, but find the right counter and it's super effective. Also in the later chapters there will be mages and mage killers. Selten may seem like an unstoppable killing machine, but so was Fredrick from awakening. However, you have him in a room against Necromancers and Soulless casters. He is quickly screwed. That being said things were balanced. In chapter 10 on-wards some enemies will have a weapon called a mage killer. It ignores defense and has crazy range. So if you try to attack from afar it will be able to attack you back. The only tome able to attack someone with the mage killer from a far enough distance is the Helformorium. Also, there are so many weapon redesigns and things that changed since then. I feel like you should play the steam version and if these issues still exist for you I'll gladly take a look.
*Chapters 0-5 are a cake walk as well as the starting quests.
*Chapters 6- 12 are increasingly hard alongside some of the advanced quests.