I want to ask if there will be only one built queue for buildings and units or if there will be separate ones?

In most games there is only one built queue and it often irritates me that I can't construct a building while training a unit. I know this is often a balancing issue or not feasible because having separate built queus would only add complexity and has to be balanced on its own.

But given how special districts worked in EL you could have a system where you woud have to built a garrison/training ground and train your soldiers from there. A ressource could be manpower so that you can't just spam unit after unit while building your city. Also part of the food and/or industry production could be channeled to said garrison if you train troops.