I can only speak for Cardigans, but:
They bark. A LOT. Keeva is not a "spook/bark at every little noise" dog, but she absolutely barks if people approach/pass our house. She has a huge bark for her size too.
They also bark when playing and when excited. Keeva runs circles around me, wiggling and barking, to welcome me home from work.
You need to be ok with barking to own a corgi, for sure. Some are quiet but many are not. They also like to grrr and growl, which can be pretty entertaining sometimes.
You can expect a lot of cattle dog traits out of a well-bred corgi of either breed. That includes some degree of guardiness, possible dog reactivity, motion reactivity, a desire to control the movement of other animals, etc.
Being dog snarky, pushy, etc is pretty common, but rarely are they so dog reactive/aggressive/same sex aggressive that they can't manage to get along with household dogs. So bossiness, some resource guarding, etc, is normal, but out and out dog aggression is not.
You absolutely need to make inquiries about temperament, big time. As others have said they are strong-natured dogs and that can go sour quickly. My Cardi is not HA at all, really. She does guard the house and such but I don't worry about her at the vets, and she's never shown aggression towards me or my family at all. She's snarky and bossy as all hell with other dogs but has never truly fought with or hurt one - though I believe she would if pushed, so I don't let her get pushed.
Keeva actually doesn't shed THAT much, it's like... less than a GSD but more than my Mal? She has a proper coat per the standard (double coated with a ruff and thick pants, fox-brush tail) but she's closer/slicker coated than is popular in the show ring, so that could be why she doesn't shed too badly. I know Pems (and some Cardis) who shed like crazy. Her coat is delightfully self-cleaning and all weather. She never gets cold and handles heat just fine.
I don't brush her often, maybe like once a week with a rubber curry comb. I do bathe and blow her out with a forced air dryer every 4-6 wks, which IME helps the shedding enormously. IMO the trade off for the shedding is the complete lack of matts, resistance to burrs/stickers, weather proofing, and general ease of care. Although expect that you will be wiping that little belly off a lot, lol.
You need a very good sense of humor to own a corgi of any breed, LMAO. They are... enormously clever and comical. Keeva is wicked smart and very much a thinker, compared to my Mal who gleefully does what I ask her to just because. She's the kind of dog you can see weighing options constantly, lol. She also makes me laugh everyday, with her enormous ego and sassy attitude (and hilarious nubby legs). She likes to take whatever she's chewing on and "throw" it, and then pounce and act like she can't quite grab it, then bark, then zoom, then pounce on it again. LOL Hilarious little dog.
We call them Bad Short Dogs for a reason. If you like the sound of that, a corgi might be for you.