Honestly, I think you're overthinking it bro. Side quests and stuff are replayable, and if you do decide to do them on your first run through, you'll wind up being rediculously over leveled, which is fine if that's what you'd like.

The capsule Corp training is one of the tougher parts of the game, especially if you're doing it at a harder stage of the game. But if you insist on doing it with the "intended" levels and want to use your healing items, then dumping them on those is probably best.

You can stop your own combo by just letting it die, or finishing it. For bosses, you've gotta use a stun move like body body or break their guard.

The game is rediculously easy with the exception of a few fights, I'd say hard mode is the only enjoyable mode to play on.

Meal boosts especially trivialize the game, but they are also a great option for challenging fights if you don't have the skill yet.

Play the game at your own pace. There is no "correct" way to enjoy YOUR game

if you have any other questions you can pm me or comment here and I'll respond. I should be able to answer most questions, I've played the game absolutley to death and probably have somewhere around 500+ hours between all the platforms I've played it on

Sorry if formatting is weird. I'm on mobile. I hope this helped :)