He had 5 receptions for 81 yards and a TD. He followed that up with 2 receptions for 28 yards and a TD and 6 receptions for 77 yards and a TD. That was during Games #2, #3, and #4 with the Rams. Your claim that it took "weeks" for him to become "integral to the offense" is false. Unless "weeks" means a couple weeks. And in that case, a WR we acquired would have a couple weeks before we played Green Bay.The majority of those yards came on the 1 bomb. His #s were pretty pedestrian for weeks after that.
Also, neither Downs or Allen are 2021-era OBJ interms of pure ability. Allen is solid but I'm not losing any sleep about him becomin a 49er.