I agree with @elisehdy and manual connection would be a better fit in this case. +1 from me for granting FromGtoG manual connection to the removable media interface (#voteFor). Just realized that removable can always be manually connected without any special snap-declaration.
Similar to Noc-convert: auto-connection request for removable-media - #9 by jslarraz, the usual guidance in this case is to use snapctl is-connected to detect if the removable-media interface is already connected and prompt the user to manually connect it when needed