I've got a dachshund cross.
They're noisy, opinionated, notoriously hard to toilet train, highly unlikely to win prizes for obedience (not because they're thick, just stubborn), like digging (as my newly seeded lawn can attest), will happily walk for miles, definitely aren't couch potatoes.... and did I mention how many opinions they have? They're fiesty too, having been bred to go down badger setts and hunt them - if you haven't been bitten by your own dog in the last week, do you really have a dachshund...? [Not needing stitches level biting, but opinionated nipping....]
Mine hasn't had any health problems yet (touch wood) but the plural of anecdote isn't data. There are more robust breeds out there (like Jack Russells) and some health disasters (like French bulldogs, English bulldogs and pugs). They're not disasters in the health department but IVDD is a genuine concern.
I love mine to pieces but they wouldn't be half as popular if they didn't look the way they do. They're not for people who want a nice easy family dog, but they do have their fans with people who have strings of them.
I agree with PP that getting two puppies at a same or similar time is a recipe for disaster due to littermate syndrome. If you want two, but one and get it fully trained and then get another when the first is around 18 months - 2 years+, or seek a bonded pair from a rescue. While you may not believe in only having one dog, some dogs do prefer to be an only dog, mine included (some of the muddled info I have on his background includes him being rehomed by his first owners for not getting on with other resident dogs, and I can well believe it tbh).