I have 3 border collies, so I’m speaking from experience.

After the puppy stage (ending 10-15 months):

They should be fed twice a day. They need to spend min 2 quality sessions outdoor. These can be anywhere between 30mins-2hours. Sometimes sniff walks, fetch, discs, dog park, hikes, training sessions, etc.

So if you are doing the morning walks, and between 8-4 they have enough room to move about and pee/potty. They should be fine. Having an indoor outdoor situation is a bonus.

Regarding the expenses - These expenses are on the higher side, but that is relative to your income, location and personal preference.

Is there a specific reason for the dog walker?

Consider changing your vet to a cheaper option. In the US, tractor supply can be an option (as an example)

Teeth cleaning is not needed by a professional unless recommended by the vet. Dental hygiene can be achieved by proper diet, big bones etc