Go to your game files an locate the Nyaruru folder
Open js then nya (C:\..\SteamLibrary\steamapps\common\Nyaruru\js\nya)
To disable the checks for item consumtion and getting hit open: nya_statem.js (any texteditor will do)
Use STRG-F to search for: Game_Player.prototype.triggerBossScore
Replace both ot true statements with a false statements
It shoud look like this:

Game_Player.prototype.triggerBossScoreOnHit = function() {
if(this._bossScoreRecording && !this._bossScoreOnHit) {
this._bossScoreOnHit = false;
}
};

Game_Player.prototype.triggerBossScoreUseConsumables = function() {
if(this._bossScoreRecording && !this._bossScoreUseConsumables) {
this._bossScoreUseConsumables = false;
}
};

To get more health open: nya_game_system.js
Search for battleObject().hp
replace with
Game_System.prototype.adjustDifficultyHp = function(oldmhp) {
$gamePlayer.battleObject().hp = 10000;
};

The edits in the first file will disable checks for item consumtion and getting hit, while the second one will set your hp to 10000 AFTER changing difficulty in game.

Maybe there are better ways, but this was the first I found.
Enjoy!

If you want to undo the changes, simply right click on nyaruru in your library, go to properties and verify file integrity. Steam will re-download the modified files.