Hi OP, I do need to apologise to you for at least one thing, and that is that when I started my reply to you, you had only made your first post, but unfortunately due to a lot of things happening in a reasonably short space of time here (at my home), I couldn't finish my response to you for a while, and as I only have my phone I couldn't check what other replys you had received, or given without losing what I had already written.
I have since re-read your OP several times, and as a stand alone I still garner from it the information that you wanted to leave your 12 week old puppy (who at the most would have only been seperated from his mum and siblings for 4 weeks) alone locked in his cage so that you could go out, to me, that meant for hours on end, maybe even all day when you went back to work or a day out! You said something along the lines of you felt like giving up on the training you had already given him, that he wasn't progressing quickly enough for you, and that you were already worried that you might start resenting him. To me, your first post seemed to be very much about you, and how your needs weren't being met, rather than worrying about how your 12 week old pup's needs were obviously not being met (LadyCatStark is probably going to have another go at me for that). I simply could not, in any way, sit back and let you think that locking a young puppy who needs it's family (who are now you and the rest of your family, rather than his mum and siblings) into a small cage for hours on end - infact no matter whatever their age, a dog (or any animal) should not be locked up for hours, under those circumstances, unless you know it is asleep, as at nightime. So that post made me think that MAYBE your home circumstances meant that having a puppy was not suitable for you, I was not blaming you for trying, I was not accusing you of being a horrible person, I just felt that you should know that it would be ok to rehome him if you couldn't, or didn't want to cope with him, because as he was such a young pup, it should be easy to find a suitable home for him, where he could be left in a room when his family had to go out, rather than in a small cage. At no time did I say that that was the only fair thing to do, I tried to explain how much time and energy a puppy takes (you did start off by saying that you had never had a puppy before), and I suggested that if you kept him, you got some professional training for you both - that wasn't meant as an insult, it would be advisable for all first-time puppy owners to get training for both them and their dog. In fact lots of people still take new puppies to training (amongst other things it helps to socialise them) even when they are very experienced puppy owners, or maybe even because they are!
In your later posts (please remember that I hadn't read them before posting my response to your OP) you made it clear that you only meant to leave your puppy for up to a couple of hours, and not very often anyway, that is very different to what I originally thought, and I don't know which of us is to blame for that - if indeed we need to blame anyone! However, whilst your puppy is awake, the only time I believe it to be ok to leave him in his cage, is when the door is open. I also noticed that in a later post you tried him in a playpen (much preferable for an awake puppy, as long as it has everything he needs in it, and he has room to move about), but that he jumped out - is he a baby Weimaraner 😂 Would it be possible to make the bars taller so that he can't jump out whilst you are out, or upstairs, until housetrained? I was very relieved to hear that you intend to take him to doggy daycare during your longer absences, he should love that, and I was very touched to read that you slept by your puppy's cage for the first few nights until he settled. I was also glad that you had indeed read up about puppies before you bought one, and that you are indeed invested in him. Please do be prepared for some toilet accidents from him for a while yet (and probably again when he is old - it is very sad then, because you know the end is coming, which is very traumatising, and the years fly by so quickly...) I hope that all of you have a lovely life together.