Where the work happens
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Spice needs less from a space than almost any food process, and the one thing it does need is the thing most spaces are worst at.
What the room has to do
No cooking, no cold chain, no drainage requirement, no hot water for process. You need surfaces you can clean, storage you can seal, and somewhere to put a scale.
What you do need is control of the air, and that is a harder ask than it sounds.
Humidity is the specification
Below 55 to 60 percent relative humidity, because above that there is enough water vapor to bridge particles together into a cake. A powder open on a bench in a humid room absorbs moisture continuously, and the moment you seal a jar you have captured that air against the product for the life of it.
Also avoid temperature gradients. Moisture migrates into dry powder from warmer surroundings, so a store against an outside wall or under a hot roof is a wet store regardless of the average reading.
A hygrometer costs almost nothing and tells you whether today is a filling day.
Separation of strong materials
Aroma moves through air, and sealed containers protect the room from the contents as much as the contents from the room. Cumin, asafoetida, fenugreek and clove will find their way into everything stored nearby.
The practical answer is sealed bulk storage rather than open bins, the strongest materials physically apart, and empty jars kept closed rather than waiting open on a bench in your aroma.
Home, rented or shared
Many jurisdictions treat packing dry shelf-stable spice far more lightly than food preparation, which makes a home operation genuinely viable at small scale. Confirm your own rules rather than assuming, because cottage food regimes vary enormously and some exclude anything sold wholesale or online.
A shared commercial kitchen solves the regulatory question and creates an aroma one, since you do not control what else is in the building. A dedicated small unit is the eventual answer and it is usually driven by storage volume rather than by process needs.