This info may have already been covered, but I don't have time to read 7 pages, so sorry if it has.
First thing to do is to raise the stem, I did read on the first page that someone recommended the Nitto Technomic stem and that is a solid recommendation. Keep in mind that the higher the stem goes the more back your body will go, ideally when your hands are on the hoods, the bar should cover the front hub, so if that is currently happening with your current setup raising the bar is going to put that bar behind the hub, so if that is the current situation then you will need a slightly longer reach on the stem.
However your current stem looks a tad low, you might have some room to raise the stem up unless you're at the limit line now, but it doesn't appear you should be, I would do that first before buying a new stem because it's the cheapest thing to try.
The other issue you need to look at is your seat positioning, again ideally when sitting on your seat with the pedals at 3 and 9 o'clock positions is that with the foot at the 3 position you dangle a slightly weighted line off the tip/end of the kneecap, that line should intersect your foot and be at the pedal axle, if that line falls behind the pedal axle you should move your seat forward till it does, doing so pushes your body more forward on the bike.
I would make sure the seat adjustment is correct BEFORE replacing the stem, why? because again it's the cheapest thing to do! Once you have done that and a change was needed, then ride the bike to see if it improved any, along with raising the stem, if not then go with a different stem.
Another seat-related item is the seat itself, some seats have longer rails, giving you more movement, that particular seat rail, from what I can tell from the photo, appears to be quite short, but the picture is not good enough for me to know for sure.
I would not recommend replacing the drop handlebars with a flat bar, once you've done that you will have fewer hand positions to move around with to stay comfortable on long rides, short rides you would be fine with straight bars, so depends on how much you ride, some people can tolerate no alternative hand positions on long rides, most cannot. What you could do is go with a new set of drop bars called a shallow drop, you currently have the old-school deep drop bars.
Your brake lever position looked ok to me, raising up the brake levers might make it more difficult to activate the lever, but you have to be the judge of that.
This is all speculative because we can't be there with you to watch you ride your bike to understand what to do, so you're going to have to play with it. It might be worthwhile to take the bike to a bike shop and have them look at it with you on the bike, to see if they have any recommendations.