When you have a gravel bike, the key word being gravel, what do you want? A bikepacking handlebar harness to hold a dry bag or a conventional handlebar bag?

You should have no problems with a conventional handlebar bag.

If the steerer tube is metal, and if you have sufficient steerer tube to take a second stem, I prefer that for handlebar bag mounting. A short stub of handlebar or metal tubing in that second stem can fit lower than the handlebar to mount the bag lower and a bit closer to the steering axis.

The bag in the photo is no longer made, plus I made modifications to it, I do not recommend this bag. Photo is intended to show the concept of second stem.



Thorn makes an accessory T bar that works the same way, it consumes only an inch of steerer tube, but shipping from UK can be pricey. I use that on a bike instead of a second stem because I only had 25mm of spacers on the steerer tube that I could remove.
https://www.sjscycles.co.uk/accessor...0-deg/?geoc=US

Make sure you include shifting in your measurements. In this case the lever clears the bag side pocket but if the bag was higher it would not.