I really like narrow bullhorns bc I ride like a jackass. I would recommend going to a used bike store and buying some cheapo straight bars that have the same diameter as the one you already have.

Also I have always wanted to try Butterfly Bars but never seen them nowhere. If you're not going too far and don't have too many hills, you won't benefit from that many hand positions so it probably ain't worth the cost. At most, some of them bar ends for a grip you can pull against with some cheap straight bars will do you good.

That said, I will never begrudge no one pimping out their bike. It's fun and helps you build a better relationship to your machine. Since I hurt my leg over the summer, I can't really ride more than 6-8 miles at a time so I'm not really one to talk no more lol.

The bar ends are really crimped? I thought "IsoZone" meant they put a chunk of rubber inside the bars and concealed it with a normal bar-end plug, like this. Though I wouldn't put it past Trek to do something dumb like crimp the end of the bars shut.

Back to your question: flat bars are mostly all the same, IMO. Just get one with the right clamp diameter to match your stem. If you want a specific make and model, I can vouch for the Titec Hell Bent XC bar that I'm still riding after many years.

If you want to get weird, the bikepacking folks seem to like Jones H-Bars and the like. They allow more hand positions and tons of mounting room for lights/bags/bells/whatever.