A shame to loose the address type qualifier, I know for the Vicmap import we dropped this due to complexity but in this case it was surveyed.
I'm also not sure if there are some mixed used buildings with commercial and residential that would have both Shop 1 and Unit 1 within the same address.

I think it should be okay to do `addr:unit=Shop 1`

https://wiki.openstreetmap.org/wiki/Key:addr:*#Detailed_subkeys mentions in the US there is no consensus on including the designator