Osaka luggage storage

Any recommendations for luggage storage in Osaka?

I need to send 2 x luggage from Nikko to Osaka. Due to staying in an Airbnb in Osaka, luggage storage at the accommodation is not an option. Are there luggage storage companies/services that I can ship to that will store for 2-3 days?

Luggage forward services and hold bags up to seven days before delivery.

So I am able to specify a day in the future for delivery?

Yes, generally up to D+7, D being the day you send your luggage.
For example, if your luggage takes 2 days to be "transported", you can specify a delivery date from D+2 to D+7.