I'm confused, or someone else is, or both. The OP refers to wanting a medium format focal plane shutter. This doesn't spell inexpensive, or fast. Lomography cameras like the Lubitel typically don't have a focal plane shutter, they have a between-the-lens or behind-the-lens shutter, which can be a lot smaller than a focal plane shutter. Brownies, which were also mentioned, often have a behind the lens shutter - the simple lens in a Brownie allows the shutter to be behind the lens for easier assembly, yet still relatively compact.
The reasonably practical alternatives for between or behind the lens shutters may be Packard (simple, have been around forever), Copal/Compur leaf shutters (no longer made but there are a lot of them), or designing a 3D printed shutter and servomotor controller - there is someone who has done the latter but it can only go as fast as 1/8 second or so.
People who need shutters in an optics lab might typically buy an electronic shutter and controller from a place like Uniblitz, or Thorlabs, or Edmund (who probably gets their shutters made by a contractor). These are expensive and not easily adaptable to portable photography.
I don't think buying cameras or components from a Chinese manufacturer is simple to the degree of ordering shutters on aliexpress. Building the relationship with the manufacturer surely matters. I think this working with the manufacturer is something people miss when they criticize Lomography for selling expensive plastic cameras - I doubt Lomography just sends a picture of a Lubitel or Diana overseas and says "Please make this and ship us 10,000 units."