Been shooting this fine old caliber since the mid 60's, first with factory ammo then in the late 60's with reloads.
I've tried a bunch of bullets but if you want a multi-purpose bullet that you can use for varmints, predators and white tail deer, the Sierra 85 BTHP is the one. It shoots like a match bullet and has excellent terminal performance. Powders such as IMR 4064, Varget, and IMR 4350 perform exceptional well with this bullet in my experience.
On deer, as with any caliber, shot placement is critical. If you wait for a broadside shot, slightly behind the shoulder, the 85 BTHP will drop them where they stand or at worst, they'll run a few yards and pile up. Never lost a deer to this great bullet.
Other bullets I've used that work well are the Sierra 100 grain Pro Hunter, Nosler 90 BT. Again, same powder as the 85 BTHP. For deer, it's all about shot placement. Because of supply shortages, I wouldn't hesitate to use any bullet designed for big game in this caliber. In other words, I wouldn't anguish over the bullet as long as it is designed for deer size game.
Unless your shot opportunities are beyond 250 yards, I think you'll dump the 7mm magnum once you start using the 243 Win.

 Your shoulder will thank you.

Also, don't be surprised if you shoot the 243 better than the magnum.