Basic 10Gb local / 3Gb remote access set up question

With a DS 1522+ and the Synology 10 Gbe cthernet ard installed, I am able to connect my MacBook Pro (with the OWC10 Gbe adapter) directly to the NAS following Will’s instructions and I have 10 Gb speeds working just fine when connected locally.
However, I’d also like my NAS to be connected to my home internet (I have 3 GB service) so when I am away I can max out my remote access/downloads to my NAS. Is there a setup that would allow both connections via the Synology 10Gb ethernet adapter? Would simply putting a 10 Gb switch between my router and the NAS allow the NAS to utllize the 3 GB internet AND the 10 GB local connection at the same time? If I am on the local network connected directly to the 10 Gb port, then my NAS is only connected to my router through a single 1 Gb LAN port, thus not taking advantage of the 3 GB internet available to other remote users. I don’t (yet) have a managed switch or know how to LINK aggregate the 4 ports on the NAS, but hoping someone here can walk me through how to take optimize connection speeds for both scenarios ( local 10G network and remote 3 G network). I understand that remote access will often by limited by my remote internet speeds, but I often have access to > 1 GB networks and would like the simplest/fastest remote access - TY in advance.