I think you need to learn how to play.
If open spaces are a disadvantage then that's all there is to say about it. There isn't room for 'but it is negated' primarily because the other faction has automatics and semis as well. If you say it comes down to who sees who first, then positioning is pretty much going to be king with the queen being of how aware are you (and how well your game senses are). If you're having trouble with a bolt, then I suggest you stay away from it and stop deriving conclusions from your poor usage. For every second that you experience there will be contrary ones.
Overall, I would say your issue is a learn2play issue more than anything else.
Also, secure territory by being proactive, let the other fodder and lemmings sit in an area while you attempt to spawn kill. That's how you should play pubs because that's what they're there for ... for you to stomp.
I'm usually one of the first people in an objective, and I'm well aware that the rifle is going to be disadvantaged as a result of me being in close quarters with the enemy. My score consists almost entirely of getting into or trying to defend objectives. I've read about the experiences of other rifle-players, and I've played the game with the weapons for a considerable amount of time. Before I move on to playing more with the other weapons, I want to master the rifle.
What I'm actually trying to say is that, in terms of firepower, I feel the rifle doesn't really have a discernible advantage over other weapons over open distances. It's a matter of the ballistics that I'm concerned about.
While you will dismiss me as a whiny Ostfront veteran who doesn't want to learn to play, it's not connected to being too used to the recoil-heavy, unrealistic SMGs in RO1. In terms of handling, the RO2 submachine guns seem pretty realistic - though I think the PPSh might have too much recoil. That's not what I have a problem with.
I can shoot somebody in this game with a rifle round, in the arm, leg, chest, whatever, and I see them simply bandage it in the time it takes to re-bolt and line up my next shot. That's assuming my round even hits the target, with questionable hit detection. Meanwhile, at distances ranging 150 meters or more, the submachine gun rounds seem to be just as pinpoint and deadly as they are in close range, in spite of being pistol rounds. The effective range as I know it is up to 200 meters, but I would expect a tapering off in killing power and more apparent bullet drop as you near and surpass that mark.
Also, while Stalingrad was basically one gigantic urban mess of close quarters combat, the distribution of some of the assault weapons is questionable. The MP40 was vastly outnumbered by PPShs to the degree that German assault teams used captured Soviet weapons to make up for the fact that German infantry had shortages of automatic weapons. In this game, on the other hand, I see more Russians using captured German assault rifles and MP40s than vice-versa.