There are a lot of variables in frame design so too many things to respond to in a totally custom frame.
Your reach of 388 is really long for someone of your height. 375 is more typical for a 50-52 cm frame. And then a stem length of 100 mm is, I think, going to be way too long.
Of course a lot depends on the terrain you ride. In New England (where I live) the gravel roads tend to be steep and descents are fast, so when I get a new frame it will have slacker HTA than my current 70 degree (which is already slacker than the vast majority) and I'll go with 50 mm offset fork. I'll increase reach 10 mm from current as well and go with a shorter stem. BTW - I'm same height as the OP and my stack is 573. If you want a more upright position (which I think you do on a gravel bike) you'll want a taller stack.