Dog Ownership Advice Needed - Will it work?

I need some honest advice about whether my bf and I are realistically able to own a dog at this point in our lives.
Firstly we are both very outdoorsy / active people and I have already have extensive experiences with both dogs and horses growing up - so I am no stranger to the realities of pet ownership! So in many ways we would make ideal owners but there are a couple things that are leaving me unsure as to what is possible.

I am currently finishing my full-time undergrad degree with 2 years remaining whereas he is in the RAF. My logic follows that it is most sensible for us to get a puppy whilst I am still at university. This way I can take advantage of the long summer holidays in order to give said puppy unlimited amounts of attention needed in the early stages. My course has a very low number of contacts hours (less than 8 per week) so I would be able to devote a large amount of time during the term as well.

On finishing my degree I will be hoping to work full-time. I will be looking at a commute of at least 45 minutes and so I would be unable to come back to the house during my lunch break. My bf rotates day and night shifts weekly so he would be around during the day every other week and we agreed we get a walker for the other weeks. My issue is that roughly once every year my bf is out on deployment for 2-3 months. During this period it is likely would need to rely on a dog walker everyday during the week whilst I am at work. This would be expensive at around £50 a week (£600 for 3 months!) and whilst we would not begrudge spending the money if needed, I am unsure as to whether this is fair on the dog.

In summary, what are people's opinions on relying on a dog walker for extended periods of time? If I am out of the house for 9-10 hours a day is it unlikely I can care for the dog whilst he is away? Is it sensible to get one whilst I have the time before I work full or wait until our circumstances change in the future?

I appreciate I may be being overly cautious but I want to make the right decision.

Any advice is appreciated!