I have 4 Nagants and 2 of them are 91/30's. A bullpup infantry rifle based on that is a massively bad idea.
1. You have no way to cycle the bolt without removing it from your shoulder. Solution is to make it into a semi-auto like a Garand or SKS. You need a gas-exchange system to cycle the bolt.
There was only 1 obscure bullpup bolt action made in that era and it tried to solve the above problems but failed miserably. Basically they budged the trigger by a few inches.
2. The kick on a full 1892 is a beast. And that's with a big frame to absorb a lot of the recoil. The 1944 doesn't burn as much powder so it's not bad. A bullpup done properly is pushing into elephant gun recoil territory, very bad for your average trooper to use effectively. The metal bits would probably make up for this but I have other issues with them below.
3. The magazine is way too ill-proportioned. It's sized for a big pistol cartridge. It needs to be about twice as wide and one third as tall for your described 5 shots of 54r. However, you notice if you do this that the mag will not even stick out of the bottom of the stock. This means you either need to increase the capacity or try a different loading method. Minimum capacity to get out of the stock would be around 12-14 I would think. You could always load a box clip Garand style from the top or a regular stripper mag classic Nagant style if you want to keep the 5 shots. Also consider ergonomics. That angled mag is a bad idea. Even the way you have it drawn you couldn't pull it out because of the pistol grip on the gun.
4. All that metal is going to make that thing super heavy, especially since you don't need it for cooling or essential parts like an SMG. When the Bullpup carbine of something weighs almost double what the full rifle does, people are going to be ticked.
5. Going back to ergonomics, there is zero reason for the pistol grip. It's good for something that you need to control barrel rise with like an SMG or Assault rifle but to use it on something that is essentially a light marksman weapon is assanine. Try to lay down and make a far shot with that thing. Not going to happen.
6. Put the classic Nagant sights on it. SMG sights don't cut it when even my 1944 has gradations to fire out to 2 miles and can do it too.
7. Add a proper foregrip.
Basically you drew a PPSH/modern bullpup mashup, and it'll take a ton of modifying to make it into a Nagant/SKS Bullpup carbine.