Rear Shifting
 

So I am experiencing rear shifting issues on my gravel bike. I have a Specialized Diverge Elite with a Shimano GRX400 group set. The drive train is a 2x10. My problem is that my shifting on the large chain ring is unsatisfactory. The shifting on the small chainring is perfect. On the large chain ring the shifting is good from high to low. When going from low to high, there are 3 clicks on the shifter that don’t do anything and then on the 4th click it will move 4 gears. It’s driving me crazy trying to figure it out. Any help would be appreciated. Thanks

possible bent/kinked Cable or Cable Housing.
possible Frayed Cable in the shifter area.

replace cable, noting any high drag while inserting new cable.
replace housing that causes any noted drag.

Tip: replace Brifter cables Regularly... once a year if you ride a lot, every Two years otherwise...
some of the Most Epic struggles reported here, and that i've experienced, are Removing the broken cable end from the Shimano brifters... it is NOT fun.
it ranks worse than getting a Shimano shift cable out of an old Campy downtube shift lever......

your symptoms point to a possibly Frayed shift Cable.
Replace Left and Right cables as PM, to avoid the Epic Struggle.

Strange that it would be ok on the small chain ring but definitely “frayed cable inside shifter” symptoms.

The shifting in the rear changing with different gears in front usually means that either the BB cable guide is loose and moving as the front is shifted, or that the internal cables are crossed over each other.

You didn't say if it was always like this or it suddenly started on its own.

Always start from the beginning to eliminate as much as possible.
check rear der hanger alignment with tool...w/o tool is a failure
check shifter/cable/housing by removing cable at rear der and holding cable end in one hand shift up and down with a bit of tension on the cable to see if the shifter is working properly and can also feel for binding of cable in housing
check rear der manually to make sure it flows up and down smoothly...just move it with your hand
if cable/housing is several years old...replace...part of maintenance
there is much more but this is the basics for what you are asking about