When you use the instrument to cast a spell that causes targets to become charmed on a failed save, the targets have disadvantage on the saving throw. This effect applies whether you are using the instrument as the source of the spell or as a spellcasting focus.

Some spells clearly state in their description that the target “is charmed” if it fails its saving throw (ex: Hypnotic Pattern). Other spells don’t state this, but do state that “creatures that can’t be charmed are unaffected” (ex: Otto’s irresistible Dance).

Are those spells that don't state the Charmed condition, but state the Charmed aren't effected, considered as charm spells as well (thus enabling an Instrument of the Bard wielder to impose disadvantage on their saving throws as well)  ?

When you use the instrument to cast a spell that causes targets to become charmed on a failed save, the targets have disadvantage on the saving throw. This effect applies whether you are using the instrument as the source of the spell or as a spellcasting focus.

Some spells clearly state in their description that the target “is charmed” if it fails its saving throw (ex: Hypnotic Pattern). Other spells don’t state this, but do state that “creatures that can’t be charmed are unaffected” (ex: Otto’s irresistible Dance).

Are those spells that don't state the Charmed condition, but state those with immunity to Charmed aren't effected, considered as charm spells as well (thus enabling an Instrument of the Bard wielder to impose disadvantage on their saving throws as well)?

While attuned to an Instrument of the Bards and using it as your bard spellcasting focus, you can give your targets disadvantage on saving throws against charm spells you cast.

Some spells clearly state in their description that the target “is charmed” if it fails its saving throw (ex: Hypnotic Pattern). Other spells don’t state this, but do state that “creatures that can’t be charmed are unaffected” (ex: Otto’s irresistible Dance).

Are those spells considered as charm spells as well (thus enabling an Instrument of the Bard wielder to impose disadvantage on their saving throws as well) ?

When you use the instrument to cast a spell that causes targets to become charmed on a failed save, the targets have disadvantage on the saving throw. This effect applies whether you are using the instrument as the source of the spell or as a spellcasting focus.

Some spells clearly state in their description that the target “is charmed” if it fails its saving throw (ex: Hypnotic Pattern). Other spells don’t state this, but do state that “creatures that can’t be charmed are unaffected” (ex: Otto’s irresistible Dance).

Are those spells that don't state the Charmed condition, but state the Charmed aren't effected, considered as charm spells as well (thus enabling an Instrument of the Bard wielder to impose disadvantage on their saving throws as well) ?