Drinking an elixir explicitly requires an actionIt doesn't matter
The Rogue's feature saysExperimental Elixir requires an action:
Fast Hands
Starting at 3rd level, you can use the bonus As an action granted by your Cunning Action to make a Dexterity (Sleight of Hand) check, use your thieves’ tools to disarm a trap or open a lock, or takecreature can drink the Use an Object action.elixir
So you can Use an Object as a bonus action, unless there is a rule witch says otherwise, since specific beats genericWhich means Fast Hands isn't applicable according to DMG p.
For instance, drinking a potion requires 141 "Activating an action because the rules says soItem":
Drinking or administering a potion takesIf an item requires an action.
Therefore, you can not drink a potion using the Fast Hands feature.
Experimental Elixir has a similar wording:
As to activate, that action isn't a function of the Use an Item action, so a creature can drinkfeature such as the elixirrogue's Fast Hands can't be used to activate the item.
ThereforeMagical or not, you still can't do it as a bonus action nor use the free object interacion. You have to expend an action in order to drink thean elixir using the Fast Hands feature.