They're sham elections because any election being held by an occupying force about wanting to join the occupying force cannot be shown to be without coercion, even with international observers. Especially after the discoveries from Bucha, Izium and other places.

On top of that, there's the fact that large portions of the residents were forced out by the war, especially the residents inclined towards Ukraine. So the fact that they don't get a say also makes these elections a joke.

International observers recognized this, thus they refused to oversee the elections. It's a pretty shrewd move to request international observers, since if they had accepted they would've appeared to be giving Russia legitimacy (regardless of what they said) and by refusing they've given Russia the ability to claim to useful idiots that they were trying to act in good faith by asking for international oversight but the West was acting in bad faith.