New puppy advice

My partner and I are thinking about getting a dachshund puppy.

We have a house with a garden and we both work relatively short hours: 8:30-4:30. I also work only 5 hours one day a week.

I live a 10 minute walk from my office and so the plan will be as follows:

Walk in the morning before we go to work (length of walk increasing as the puppy gets older as I've read they can't walk as far when they are very small)

Crate train until lunch time when I will be able to come home for an hour, let the puppy out into the garden to toilet, play with him/her then return to work until 4:30.

So the puppy will be alone for 3 and 1/2 hours with a break and then another 3 1/2 hours. I wanted advice as to whether people think this is a suitable routine or whether we should pay for a dog walker or sitter to come in also during the day especially when the puppy is very small. I plan on taking a few weeks off work when we first get the puppy to gradually build up the time it is away from us and to let it start to associate the crate with sleep/treats to make sure it doesn't see it as a punishment.

We don't have any other pets and we don't have any children, although we do plan on having children in the next 5 years so anyones experience regarding dachshund's and children would be appreciated also!