TBH, I'd return the bar ends unopened under the DSRs if you are as strapped for cash as many of us, as I think standard bar ends, which move your weight even further forward, will make your problem worse.
What is your hand position on the bike? I ask because my son also has ergo grips and your post reminded me that he rides with his wrists very bent and a lot of weight on the soft part of the grip, sort of like
this, and that gives him wrist ache after only 10 miles. Ride with your wrists straight, like
this and relax your shoulders and I think your problem will be a free fix.
Give it a try at least, be very conscious of keeping your wrists straight and your shoulders relaxed for a 60-minute ride and see how that feels. It'll cost nothing (and be an excuse for a ride


)