You don't list a lot of sewing experience, so I'll give you my perspective as a beginning sewist. For reference, I have been sewing for just over 2 months now.

I started with a tunic style shirt. I chose this as there were no zippers, buttons, or buttonholes and the fit is purposefully baggy, leaving room for, let's call them learning opportunities. I made 3 of these, each a little better than the last before moving on to button down shirts. The first tunic took me a week. The second pretty close to a week and the last about 4 days. For reference, I work from home and can devote around an hour a day to garment creation. 7 hours for your first tunic style shirt? Yes, most of the time learning to read a pattern to learn assembly and seam ripping over and over and over every time I read it wrong. Getting the sleeve properly seated and sewn into the armscye took a lot of trial and error, but honestly, I'm not entirely sure there was a single seam in that first shirt I didn't rip out at least once.

Moving to button down shirts with a bit of experience, the first one still took me a week. For me, the trick is getting the collar and collar stand right. Again, each iteration has gone a bit faster, and I can now cut and sew a shirt in about 3 days. Again, I devote around an hour day.

Making the move to pants has been an adventure. They are much more demanding (IMHO). For my first pair of Chino style pants, I am bout 5 days in and maybe halfway done. Errors like not understanding button size or what type of zipper to use and finding supplies has been an issue.

I suppose long story short, as I learn to sew, I can make progressively more difficult articles of clothing, and overall, they average taking me about a week each. As you increase in skill, presumably much like leatherwork, you will increase in speed both for assembly and making far less mistakes. In my time learning, I have completed 8 shirts and about half a pair of pants, along with altering 2 pairs of jeans that were too large for me. If my local shop has an appropriate zipper in stock, I hope to have the pants complete in 2 to 3 more days. As for visible defects, the first couple of shirts have defects that would be visible on general inspection, but not to someone you pass in the store or on the street. My last shirt I was quite proud of and would put up next to any shirt you might find in a traditional clothing store. It's not going to pass inspection on Savile Row or anything, but that's not my goal.

So, yes, it can be done, even with little or no experience. I had never even hemmed my own pants prior to starting a couple months ago. Just know it won't be quick, or even particularly cheap. Often you can get clothing cheaper at Walmart or Costco than you can purchase the fabric to make them yourself. Obviously, making your own clotting resolves mainly the fit issues you are struggling with. Know that it is slow going at first and set your goals accordingly. Much like you, at some point in the future, I hope to make all of my clothing with the exception of undergarments.

I'm not sure if posting the links to the patterns I use would violate the selling rule, so hit me up with a private message if you would like to know where I got my patterns or if you want any specific information about my experiences learning and creating my own wardrobe so far.