I have had dogs before. We had a dog as a child, ( im older so it ran free) .. i then lived with my sibling for a few years . He had a big dog so we shared looking after it.
I then rescued another dog who was going to be put down because it was destructive. The family couldn't cope with the young dog of 9 months) but I couldn't hear of it being put down so on impulse i said I would take it. My brother was thankfully understanding so the 2 of us looked after both dogs. When i eventually moved out to live with my boyfriend we both had full time jobs but I in particular had a very long commute. It only worked out as we had a family member delighted to walk him for me 2 or 3 times per day. When we split and I moved out and closer to my job it was very challenging because I was living somewhere I didn't really know anyone who could walk my dog and i was not financially in a place to get a dog walker which weren't really a thing at the time. I worked full time in a job that wasnt very forgiving. So I had to get up at 6 am walk the dog , race home at lunchtime , and race home after work. Traffic jams were the worst as I was so anxious for the dog. The poor dog wasnt used to this and on occasion had ripped up newspapers and his bedding . By this stage he was elderly and eventually had to be put down as he had cancer. The guilt was terrible. This was about 25 years ago.
I love dogs, but I only recently got another dog as a retiree. I joke that I felt like a single parent...sometimes not getting washed or dressed until midday. 😆
He is a terrier and I invested alot of time toileting and training him. That effort meant I didnt have a destructive dog so bar a few bits of clothing, a table leg, remote control and a pair of trainers they were the only things that suffered from his shark teeth. When he was 18 months old i used doggy day care twice a week thinking I was doing the right thing, i really wasn't. He loved it but as someone else has said it meant he thought meeting every dog was mandatory which caused issues on walks.
As a pup in the winter months I got up several times in the night to toilet him. His bladder had the capacity of a teaspoon initially. I crated him at night and through the day, periodically letting him out for play exercise training and stimulation. ( It isnt just about walking the dog) . Crating was something I wasnt used to and initially thought wasnt 'nice' but reading around and researching it realised it was a good thing for my dog to rest between periods of exercise etc.
I used a dog trainer and took him to some training as a pup but while it was beneficial I didnt pursue it as my pup was so easily distracted by, and distracting to the other dogs.
I watched alot of online dog trainers , learnt ways of bonding with my dog and played with him alot which also helped with obedience.
I am saying all this because it demonstrates that I had a fair amount of previous experience with dogs, and the effort involved in having a dig. Life throws curveballs and as much as I would have loved to have a dog sooner over the last 25 years but i didnt because they are a huge time commitment especially when you are on your own, It really isnt fair to leave a dog for long hours on their own they're social beings and dependent on breed will have their own foibles . As a terrier mine needs to have his high prey drive needs met with games suited for sniffing out things, using a flirt pole and walking on and off lead as appropriate. He has good recall but by no means is he perfect. He still steals things with great glee, and digs up my garden when bored, barks a fair bit rolls in poo and dead animals. My whole world rotates around my dog he is never left for more than 3 to 4 hours and is walked before and after this. On inclement stormy days he is played with and given hunting games ..eg i hide bits of biscuits in the furniture and he has to find them. Despite how good he is ive had episodes of vomiting and the odd random poo, from him ...not me. 😀
I fell and chipped a bone some months ago, meaning I couldn't walk for about 4 weeks . Had to wear a boot, which thankfully healed quickly. I am very lucky though and I had family who could take him for some of it and the rest I got a dog walker in daily to walk him.
There is a saying when we make plans god laughs. So as much as you may think your dog will fit neatly into those plans and timelines for now then be prepared to have them upended.
My honest advice is dont do it, it wouldnt be fair to leave the pup or young dog for long periods every day. You wouldnt invite someone to your house and leave them there all day until you got back from work.