Visiting Guest Relations is a good idea, but be aware that in Dec 2020, Disney changed their list and found procedures to make the online form mentioned above, be the start of the process. From experience, it works well. In early December, we left DHS forgetting that we had put stuff in a locker. I contacted GR the next day. There was initially a lot of confusion on the part of the GR staff as the process had just changed and while they knew that, they weren't entirely sure how to proceed. It took most of the day and multiple checks back in with GR, but eventually I spoke with Emily at Epcot. She called everyone she knew of around the resort and finally directed me to the online form. Filled it out with all the details. Had an email the next morning telling me they had our stuff and that I could pick it up at the lost and found window located by the bus stop at Disney Springs. Super easy once we knew the process.
Steve