Option3. You don’t have to restore it or part it out. Keep it, use it and enjoy it and watch the parts on it appreciate over time. Better than money in the bank!
If it still works you have a shooter.
Or just hoard it away and sell it later.
You could go custom and give it that MP38/40 or Sten look by adding on a folding
or non folding stock to a homemade wood or fibreglass stock.
I restored a duv44 in the 90’s. I only paid $225 for it at a gun store, a vet brought it in. I still have it.
It came with gcb mag and an acw mag for an extra $40. It needed an original stock for $600 (a bcd stock) that I bought on this forum, and parts from a few other members. Got the small parts I needed from Sarco when they had almost everything.
It was still expensive back then but it’s a lot more now. It is satisfying restoring a gun as it comes together piece by piece. I too thought of parting it out back then but I’m glad I didn’t.