Temperament will vary widely depending on how well the dog is bred and socialized, which is why it is so critically important to obtain a puppy (if that's what you're looking for) from a responsible breeder who shows their dogs in conformation or even agility. Those are the individuals most knowledgeable about how best to improve the breed physically, mentally and socially.
I've known well-bred Maltese who were very sweet, loving, playful when young, and great companions. I've also known of Maltese from breeders who were just trying to put two dogs together who were timid, nervous, and unfriendly little dogs.
You should also consider rescues especially from groups like Northcentral Maltese Rescue or American Maltese Association Rescue - our dogs are all in foster homes so you will have a lot of information about their temperament and how they get along with other people and other dogs.
My Maltese pup is 16 weeks (had her for 4 weeks now) and I call her baby shark on crack 🤣. I'm a first time pet owner, and my pup is still a baby, but right now she's super energetic. Her breeder called her spunky. She's a creeper (moves very silently lol) and a velcro. She always has her eyes on me (cue the song "Somebody's Watching Me" ) and she always has to be touching me or laying on my lap, unless she's too hot. When they say Maltese are lap dogs...they are literally glued to your lap (which I don't mind, but my back and butt muscles pay the price sometimes b/c i'm reluctant to move)
She jumps... A LOT when she's excited. She's like a popping popcorn lol. When I'm on the couch and she's on the floor, she starts to pout, she's too small to join me on the couch yet and not fully potty trained. She's excited by other people (not in groups) and tends to piddle pee from excitement. She also runs in circles around you when she's super revved up. She's hyper when she's excited, calm and chill when things are quiet and mellow.
When she's in her comfort zone, she's confident and prances around (her puppy prancing is so cute). But when not in her comfort zone, she's very nervous, timid and shy, which I was initially worried about but I think that's a normal process for puppies and she's steadily gaining more confidence with more exposure and time.
Overall, I agree she's pretty spunky, sweet, clingy, and overall a very hyper rascal lol.
She's still a puppy so she might mellow out as she gets older but oh boy is she full of energy and takes a lot to tire her out (she isn't fully vaccinated yet so she can't walk outside).