I believe having a 223 class rifle is always a good thing for practicing but think there are better all-purpose deer cartridges.
Buy a 204 AND put a muzzle brake on your 7-08 then shoot it only when deer hunting. Get 204 on a similar platform as your 7-08; try 120’s and Varget or H 4895.
You will scratch the new rifle itch and still have a very effective deer hunting rifle.