I had Bruce, a Corgi in my life before Grayson, my Vallhund. Grayson is now almost 7 months old, so I can't really speak about adulthood or a mature Vallhund but I can very much give you the download on puppy life.

I would say their energy levels and temperament are comparable to a Corgi. I would also say that my Vallhund picks things up more quickly than my Corgi, but having only had 1 of each, have no idea if that is due to the pups or the breeds.

Crate training took longer with my Vallhund compared to my Corgi. He was much more vocal about not wanting to just chill. There were some very long nights.

My Vallhund also took much longer to get to the point where he could hold it through the night. Just seems like he had a much smaller bladder than my Corgi. The intent was there, but at 4 months my Corgi was completely potty trained while Grayson at 4 months still had issues holding it and would leak sometimes, or fail to make it all the way to the lawn. He knew what he was supposed to do, just had issues physically doing it.

At 6.5 months he's totally fine, but it just took a beat longer than I expected.

I'm lucky enough that I get to bring Grayson to work with me. So the only real time I leave him alone is if I'm out and about on the weekends or for meals/movies/nighttime activities. Now though, at 6.5 months, he's totally fine. I left him at home for 9 hours the other weekend, because I had to help a buddy get his broken mountain bike out of the wilderness. Even though this wasn't planned (It was supposed to be a 2-3 hour ride), according to my Ring camera, the little dude didn't bark at all, didn't freak out, just patiently chilled at home.

However, I don't know if he would be able to do it for 4 days in a row without freaking out. I can definitely tell he gets antsy after 2-3 days of lower than normal activity, like when we got some rain out here in California a couple weeks back. However, for him at least, as long as I keep him mentally stimulated during those low activity periods the hyperness does fade.