So the reds are currently connected to your google play account. Which is not linked to an SM account and therefore BD.
One thing i would like to stress is if you link the google play account to your SM/BD account it will over write it and you will lose all your medals and such. This is reversible (sometimes) but takes time to fix and has to be done ASAP and therefore would like to stress not to link it to your current BD account.
One method that may work would be linking your Google play account to a new BD account and therefore wouldn’t matter if you over wrote it and this would allow you send them as normal from 1 account to another on BD. (Just remember to do it on a world you are not playing and message the admin that you have no intention to play and have just planted twice to send reds over)
In theory this should work so I’ll ask @Alexander or @Malicewolf to confirm that the above is correct.
How to link a google account to a BD account
Open up SM on your phone
Go to settings
Click on the account settings
Click link to Super Mechs
Register a new account (If you login it will delete your old account)