So when taking "potting soil" out to the garden proper the first consideration needs to be soil biology, as in how much does the garden soil contain.
I always look at the "potting soil" as a form of mulch, since its primary ingredient is usually ground up trees or limbs, as such fungi will be the most important decomposers that need to be present.
As far as minerals, you would really need to get a test done on the stuff you are adding to the garden to know what is missing or in short supply.
But the first thing to address is the soil biology since that makes more of the current nutrients, both water soluble and bound up in compounds available to the plants.
Unless you are gardening on concrete or another type of paving, the soil that is under the deposited soilless mix will provide what ever microorganisms it happens to contain.
You can always boost those with mushroom slurries and some milk and perhaps well cooked rice as foods for the now present organisms.
The air is always full of bacteria and other microorganisms that will settle in and reproduce as long as there are good living conditions and available food supplies, fungi are what we normally want to add first, then we might need to take a bag of cooked rice to the woods to let it gather up some "forest" organisms for another boost to the microbiome in the garden.
Mixing that material with topsoil before applying it to the garden beds would work very well since it will then be a blend of minerals and organic matter.
However, it would still benefit more from the introduction of microorganisms, it really just depends on how much work you want to do and how much time you are willing or able to let pass by.
If you want to plant within a month of spreading the material(s) then you would probably want to add some microorganisms for the benefit of your newly installed plants or seeds.
If you are going to wait a month before planting, there would be more available organisms via settling from the air.
You always have the option of making some organism additions via watering can or sprayer or even a direct dusting of a packaged product (available at many garden centers these days).