you are getting good advice from reliable sources here, so thats a good start. Those Ergon grips, while not cheap, really are great. Ive used lots of diff grips and when I got some Ergon model similar to yours, I was immediately impressed by how the shape is very well designed, and having the bar end part is really crucial to switching hand positions regularly, for hand and back and neck slight positional changes that make a real difference.
Ive been down the same path as you, changing a late 90s mtb from its very aggressive low bar position to a more comfortable setup. That bike does have a threadless stem, so a bit easier to change stems, but in the end, I still went through numerous stem lengths and angles, and also a few diff bars, before it became more comfortable. Present bars were real cheapies, a mtb type bar but with rise (that helped get hand position higher) and also a slight angle back of the hand part, more comfortable than straight across by far.
so in other words, join the club of all of us cyclists who have a box with stems etc that were too long, too short, not angled right etc.
Dont forget used bike stores if you have one in your area, a good source for cheap stuff that will probably be scuffed, but will work fine at a fraction of price.
tires, tire choice can also help with making the bike ride nicer, but thats a whole other topic.
same with seats, as mentioned by others--not to mention using padded bike shorts, makes a huge diff in comfort, but you dont say if you use them or have ever worn them....
most important thing, ride regularly.
and use common sense for trying to determine if you need to change bar height more , or have it farther away etc.
Ride ride and ride, this is the best way for you to figure out what changes are best for you.